Jandy SWCG's "optimal" water conditions: why raise CYA?

[famousdavis]

So I've reading and re-reading all the different user manuals I got with my new pool, plus all the info available in this forum. I haven't yet tried to grasp the math that creates correspondence between free chlorine and CYA levels, but I do understand that as CYA levels go up, there is the need for higher chlorine level, too.

My Jandy-made SWCG's user manual gives the following info for "optimal pool water conditions":

Free Chlorine: 1-3ppm (Jandy adds, "Continuous exposure to levels above 3.0 PPM may cause corrosion of pool metals")
Combined Chlorine: None
pH: 7.4 - 7.6
Chlorine Stabilizer (CYA): 50-75 PPM
Total Alkalinity: 80 - 120 PPM
Calcium Hardness: 175 - 400 PPM

Then there's a place, in small print, that adjust the above for water temps above 85 degrees: "...increase the stabilizer to 75-85 PPM, and super chlorinate with other chlorine agents other than the chlorine generator, to reach break-point chlorination."

Questions:

1) Why do SWGC pools generally require higher CYA levels than non-SWCG pools?
2) Why are higher still CYA levels required for warm water (our pool is 89 or 90 degrees right now)
3) If the CYA levels are supposed to be so high, why is the "optimum" level for free chlorine still listed at the low level of 1 - 3 PPM?
4) Is it true that continuous exposure of FC that is above 4 PPM really do cause pool metals corrosion (I have a heat pump, so this point interests me)
5) Do other SWGC shock their pools with liquid chlorine / bleach instead of just using the Boost button on their SWGC?

For the techies and math geeks only: I'm only in my 8th week of pool ownership, but thus far, I've only shocked our pool using the Boost button alone (that runs the SWGC for 24 hours continuously at a 100% rate). Our model of SWGC says that it produces 567gm of chlorine in 24 hours. I've got a 16,755 gallon pool/spa, which is equivalent to about 64,000 liters. So, one 64,000 milliliters is one PPM. If my SWGC generates 567gm in 24 hours, that's nearly 9 PPM of chlorine added to the pool in 24 hours (567,000ml / 64,000ml). My Taylor K2006 kit says my CC level is 0.5 (perhaps less, but no more than), and break-point chlorination is 10 times the CC level, I'm thinking my SWGC creates enough chlorine to superchlorinate my pool once a week without me having to do anything extra.

I only just got my Taylor kit a few days ago, and I use the Boost button starting Sunday morning, so I'll be curious to see if, on Monday morning, my FC level really is 7 or 8 PPM higher than it was on Sunday morning.

Your thoughts?

[waterbear]

To answers your first question:

Higher CYA levels translate into lower cell on time which translates into less hydrogen gas generation in the cell which translates into less aeration of the water which translates into less outgassing of CO2 which is the primary cause of pH rise in salt pools (barring new curing plaster).
NOT dropping the pH below 7.6 and lowering it back down to 7.6 and not lowers (and not letting it rise above 7.8-7.9 and always keeping it below 8.0) slows pH rise (the lower you put pH the faster it rises) and helps minimize the possiblity of scaling condtitons.

Running the TA low (70 ppm seems to be optimal) translates into less carbonation n the water which translates into less outgassing of CO2 which translates into better pH stablility and slower pH rise.



For the second:
It's not warm water, it's sun exposure. If the pool temp is that high then it is assumed the pool is getting a lot of sun and higher CYA is beneficial in ANY pool, salt or not. BEST place for CYA is at the manufacturers recommended maximum so get yours up to about 80-90 ppm givin that you are in Florida (even in my N. Fl pool the temps stay in the high 80's during the summer and the pool is in a screen room!
Today my pool is at 89 degrees and it's before noon!)

for the third:
Optimum level for FC is about 5% of the CYA level, generally 4-5 ppm. This way you do not need to worry about algae outbreaks or the need to superchlorinate at all!

for #4:
It depends on a lot of factors. First, the type of metal involved (titanium and ferro cupric alloys in heat exchangers are more corrosion resistant). It depends on other ions in the water (sulfates from dry acid and non chlorine shock for example). It depends on salt level (depending on manufacturer SWCGs operate anywhere from less than 3000 ppm to sea water salt levels with most falling somewhere in the 3000-6000 ppm salt range. Even at 6000 ppm the water is not considered particularly corrosive). It depends on whether there is a sacrificial anode in the pool. It depends on pH (low pH is probably one of the biggest factors in predicting metal corrosion.)

for #5:
Shocking with the boost or superchlorinate function:
1) shortens cell life
2) causes FC level to slowly rise over the time period the boost function is on and this is not the most efficient way to superchlorinate and can actually cause some undesirable oxidation byproducts to form.
3) it is slower since you need to wait for the cell to generate enough chlorine to reach the desired level which can take as long as 24 hours just to reach shock level and then you need to wait for it to drop down after, which can take up a day or two longer.

Shocking with chlorine or bleach:
1) does not shorten cell life
2) brings the FC level up to your target shock value immediately and is therefore much more effective chemically in oxidizing and killing algae
3) the entire process is much faster since you do not have to wait for FC level to rise, it is instantaneous. You just need to wait for it to drop.

[famousdavis]

Thanks Waterbear for all your input!

I clearly don't have a handle on the chemistry that's going on in my pool. I'm a "poser" -- posing like I know something about all these chemicals when I try explaining them to my kids or my wife, but the details are still way over my head. But I'm getting there, I'm getting there.

It seems like I have a choice to make with regards to how (or to what extent) I superchlorinate my pool. I can either A) use the Boost button my SWCG, or B) go to either my nearby pool store or supermarket to buy a few jugs of liquid chlorine / bleach, and pour liquid chlorine / bleach into my pool.

The Boost / SWCG option is nice because it's dumb-easy. And since I have a variable-speed pump, I can set the pump speed to a very low setting but high enough for the flow switch in the SWCG to allow chlorine production to occur. It saves the cost of not having to buy liquid chlorine and/or bleach, and it avoids hazards that can occur with transporting and pouring those chemicals. Biggest downside, it seems, is that it may not truly achieve break-point chlorination, and it may not oxidize organics the way you'd expect. Another downside is that shortens the lifespan of the cell, so the cell would have to be replaced more quickly.

The liquid chlorine / bleach option is nice because it's very effective in superchlorinating (is that the same as "shocking"?). You can easily control how many PPMs you want in your pool by controlling the amount poured into the pool. This method extends the life of the salt cell, since I wouldn't have to Boost at all. Downsides are it costs a few bucks each week to buy the liquid chlorine / bleach, it involves trips to the local pool store or grocery on a regular basis, and it creates a chance for a spill somewhere.

Does that sound like a pretty good summation of these two options for superchlorinating?

[waterbear]

You pretty much have it down. Superchlorinating and shocking are the same. The point you are missing is that if you get your water balanced properly, get the CYA up around 80 ppm and run your FC at 5% of your CYA (for 80 ppm that would be 4 ppm FC) you will probably never need to shock the pool. Only shock if you have persistent (longer than 48 hours) combined chlorine over .5 ppm when testing with a GOOD test kit (such as the Taylor K-2006). Normally, there should be no need to shock and with the FC at 5% of the CYA you should not have algae outbreaks either (and for more algae protection and also to help stabilize pH even better the addition of 50 ppm borates to the water is highly recommended for salt pools.)

If you want to post a current set of test results I can suggest any changes you should make to the levels.

[famousdavis]

Thanks again, Waterbear.

I'll wait until the end of this week when I can post side-by-side test results from the two pool companies I've been using, plus I'll use my new K-2006 kit to give you its results, too. I'm comparing everyone's test results right now before I figure out what I'll do on an ongoing basis with regards to water testing by the pool stores (I need to do that to keep the warranty on my Diamond Brite interior). Until then, though, I'll give you some info from this weekend's readings using my K-2006.

I can tell you that the SWCG is able to boost the FC from 1.5 (yesterday morning) to 12.5 (this Monday morning) in 24 hours. And whatever trace of CC I had (during yesterday's test, the pink color for the CC test would disappear after adding just 1 drop of reagent, so I supposed the CC level was 0.5 or less), is now almost entirely gone (eg, during this morning's test, I hardly can detect any pink color at all for the CC test, but it does get very faintly more clear after adding 1 drop of reagent). Based upon my math above, I would have predicted that the FC level would have reached about 10.5 (though I rounded the liters in my pool up a little, so perhaps that accounted for some of my error. (Note: I was testing using 0.5 increments, not 0.2 increments).

Other tests from my K-2006:

TA - 80 PPM (I subsequently added 4lbs of baking soda afterwards, which should have boosted it up to about 100 PPM)
CYA - 60 PPM
pH - ranges from 7.2 to 7.8; seems happiest at 7.6. I add acid when it reaches 7.8, which lowers it to 7.2 or 7.4. This morning's reading was 7.8, so I added 4 cups of acid.

Calcium Hardness doesn't seem to be an issue -- both pool companies say I'm fine, reading between 300 and 375 depending on the week.

I am pleased that I'm getting feedback from other people who note how crystal clear our pool water is, as compared to others' pools. I attribute a lot of that to our DE filter (my buddy who supervises the City of Fort Lauderdale's public pools urged me to get a DE filter for it water-clarity benefits), but I'm sure the right pool chemicals have a lot to do with that, too. In the sunshine, the water just glistens like an aquamarine jewel. It's just gorgeous.

[waterbear]

Since you have new plaster you will have a big acid demand from the curing plaster and will go through a lot of acid for about the next year. Nature of the beast but it is very important to keep tabs on pH, TA, and CH during this time.

As I said before, the lower you put the pH the faster it will rise (and the faster you will lower TA) so you might want to rethink dropping the pH to 7.2 unless it is part of the plaster curing instructions you got from the contractor. However, SGM's Diamond Brite warranty does state that pH should be kept between 7.4-7.6. Also TA lower limit is 80 ppm on the warranty so you might want to keep it there instead of 70 ppm even though 70 ppm will give a bit better pH stability in a salt pool.
Not sure why you added baking soda to raise the TA when it was at 80 ppm. Like I said before the higher the TA the faster pH will rise and you want to slow down pH rise in your pool, particularly with curing plaster! (bringing your CYA up to 80 ppm wil also hellp as I explained).

You are lucky that your CH is not too high since that is a common problem in pools with new plaster.

Also, with a CYA of 60 ppm 12.5 ppm FC is not high enough for shocking. If you have CC of .5 greater than .5 ppm then add bleach to bring the FC up to 20 ppm. Your boost function would need closer to 48 hours to do this from what you have posted. I would not recommend that.

Also, 1.5 ppm FC is way too low and that is why you are showing CC! Your FC should be 5% of your CYA for a salt pool so for a CYa of 60 ppm your FC should be AT LEAST 3 PPM AT ALL TIMES! If you do that you will find that you do not have CC not will you be prone to algae outbreaks.

[famousdavis]

(BTW, I just subscribed to this forum thanks to your helpfulness).

I've found that whenever the pH goes to 7.2, it rises to 7.4 within the same day. So, although the pH probably was 7.2 after I added acid, it'll be 7.4 by the time I get home tonight. But I'm getting your point that shades of adjustment are better than leaps in pH adjustment; I'll re-calcualte going forward on what it takes to bring the pH down from 7.8 to 7.4, rather than 7.2.

I added the baking soda because my "optimal" range (noted by Jandy, above) is 80 - 120 PPM for TA, and since I was on the lower end of optimum, I opted to optimze my TA by bumping it an optimal middle of 100 PPM. ;-)

FC was admittedly low @ 1.5 PPM. Over the last few days of last week, I was just watching to see how my FC would fall when I ran the SWCG @ 50% for 8 hours a day. That seemed to cause it to have a net loss of about 1 PPM per day (it was 3.5 on Friday morning, 2.5 on Saturday morning, 1.5 on Sunday morning), so I know now that I'll need to bump up the salt production higher than 50%. Also, I wanted to see what my OTO kit would read, knowing it's not as accurate as the K-2006. The OTO kit is reasonably accurate (OTO showed 1.0 when my K-2006 showed 1.5; OTO showed 2.0 when my K-2006 showed 2.5; OTO showed 2.0 when my K-2006 showed 3.5). The OTO kit, however, doesn't do a good job at all at reading high levels of chlorine. As I mentioned, the K-2006 showed 12.5 FC this morning, but my OTO's yellow color this morning matched the 3.0 -- it didn't even have a bright orange color that would match the 5.0 color scale). So, it seems the OTO is good for letting me know that I have chlorine in the pool, but not so good at letting me know the upper ranges of how much chlorine. (Note: I have my elementary-aged kids do the OTO test daily).

So, in sum, it seems good to target a higher FC reading of not less than 3 PPM. Since Jandy recommends against > 4.0 PPM, while other sources say an upper range of 4 PPM is within the ideal range, I'll shoot for FC of 3 to 4 PPM. I could boost my CYA up to 80 and if I kept the FC at 4 PPM, I'd still be within the 5% of CYA.

As for shocking, I'll have to mull over that a bit to figure out what I'm willing to do. I guess weekly shocking isn't as important to do if the CC doesn't warrant it. If I just use a bleach shock maybe once a month during these warm months, maybe that's a better way to go. And I suppose I could always still hit the Boost button if I wanted, if I noticed anything less than the sparkle that I have always had in the pool so far. BTW, in a 16,000 gallon pool, how much bleach would I need? I just Googled and found a calculator that says that if my pool is 3 PPM and I want to raise it to 20 PPM, I'd need 4.5 gallons of bleach! Does that sound right? How long would we have to wait before re-entering the pool following such a shock?

One last question. I get that pool store chlorine is the same as grocery store bleach, just in a stronger concentration. Is the choice of which to use simply a financial one -- which is less costly, given how much of each liquid I'd have to add to the pool? It seems like the risk of a leaking liquid chlorine jug is greater since they're re-used over and over, and the higher concentration is more toxic, whereas the grocery store bleach is brought home, used once, then pitched into the recycle bin. It's easier for me to go to the grocery store, too, as they open early and stay open late, 7 days a week.

Thanks for your guidance, Waterbear. You've earned the site's $14 subscription fee. :-)

[waterbear]

I added the baking soda because my "optimal" range (noted by Jandy, above) is 80 - 120 PPM for TA, and since I was on the lower end of optimum, I opted to optimze my TA by bumping it an optimal middle of 100 PPM. ;-)
Except that optimal for a salt pool (or any pool using unstabilized chlorine for that matter) would be the BOTTOM of the range. Drop it back to 80 ppm.

FC was admittedly low @ 1.5 PPM. Over the last few days of last week, I was just watching to see how my FC would fall when I ran the SWCG @ 50% for 8 hours a day. That seemed to cause it to have a net loss of about 1 PPM per day (it was 3.5 on Friday morning, 2.5 on Saturday morning, 1.5 on Sunday morning), so I know now that I'll need to bump up the salt production higher than 50%. Also, I wanted to see what my OTO kit would read, knowing it's not as accurate as the K-2006. The OTO kit is reasonably accurate (OTO showed 1.0 when my K-2006 showed 1.5; OTO showed 2.0 when my K-2006 showed 2.5; OTO showed 2.0 when my K-2006 showed 3.5). The OTO kit, however, doesn't do a good job at all at reading high levels of chlorine. As I mentioned, the K-2006 showed 12.5 FC this morning, but my OTO's yellow color this morning matched the 3.0 -- it didn't even have a bright orange color that would match the 5.0 color scale). So, it seems the OTO is good for letting me know that I have chlorine in the pool, but not so good at letting me know the upper ranges of how much chlorine. (Note: I have my elementary-aged kids do the OTO test daily).

So, in sum, it seems good to target a higher FC reading of not less than 3 PPM. Since Jandy recommends against > 4.0 PPM, while other sources say an upper range of 4 PPM is within the ideal range, I'll shoot for FC of 3 to 4 PPM. I could boost my CYA up to 80 and if I kept the FC at 4 PPM, I'd still be within the 5% of CYA.
Bring the CYA up to 80 ppm and you will be able to keep the 4 ppm FC without a problem and will be able to lower your cell output. I am concerned that your unit might not be sized for your pool if running 8 hours a day at 50% is only bringing the FC to 1.5 ppm. Hopefully you have a 2 speed or multi speed pump so you can run the pump for a longer run time if needed to maintain the FC where needed. Jandy's recommendatons are based on some outdated data. If you have not done so please read the 'Best Guess Chlorine Chart' (http://www.poolsolutions.com/gd/best-guess-swimming-pool-chlorine-chart.html) for some background.

As for shocking, I'll have to mull over that a bit to figure out what I'm willing to do.
Easy answer, your don't have to do anything! Get the CYA to 80 ppm and the FC to 4 ppm and you will not need to shock. I don't know where you go the idea that you have to shock a pool on any regular basis. Last time I shocked my pool was after returning from a 2 week vacation last July and my pool was shut off while I was gone. Because of the borates in my water my pool was only slightly cloudy and a shock to 20 ppm FC took care of it and I was swimming a day later! Normally I never shock and you should not need to either!


One last question. I get that pool store chlorine is the same as grocery store bleach, just in a stronger concentration. Is the choice of which to use simply a financial one -- which is less costly, given how much of each liquid I'd have to add to the pool? It seems like the risk of a leaking liquid chlorine jug is greater since they're re-used over and over, and the higher concentration is more toxic, whereas the grocery store bleach is brought home, used once, then pitched into the recycle bin. It's easier for me to go to the grocery store, too, as they open early and stay open late, 7 days a week.
Generally pool store chlorine is less expensive here in Florida than bleach is. The carboys usually do not leak. (I have filled enough of them up myself when I worked in the biz. NOT a fun job in the hot summer sun!) The one point to remember is that the stronger the bleach the faster it loses strength. 12.5% really is not any more 'dangerous' than 6%. You need to treat all pool and household chemicals with respect. However, we tend to think of our common household products like bleach and baking soda as 'safe' because they are familiar.
For example, did you know that baking soda is actually more toxic than cyanuric acid (CYA)?
Thanks for your guidance, Waterbear. You've earned the site's $14 subscription fee. :-)

Ironic thing is that I am a moderator on a completely different pool and spa forum! :eek:I hope Ben appreciates it!;)

[famousdavis]

Waterbear,

I tested with the K-2006 kit this morning. TA is 90, pH 7.4, CH 280, FC 7.0 (the pool's still coming off Sunday's shocking), CC 0.5 (I didn't re-test CYA because it uses so much reagent).

This weekend, when I have the pros re-test the water, I'll test my CYA and do what's necessary to boost up the CYA so I can keep the FC around 4 PPM.

I got the idea that you shock a pool on a regular basis because the Pinch-a-Penny test results print-out says that that's one of the ABC's for a healthy pool -- you shock it once a week. I'm intrigued that you and others don't do this, yet don't have troubles with your pool. I thought that over time the combined chlorine becomes a problem, so shocking weekly pretty much elminates any CC you have in the water? If you only shock when the CC reaches some threshold, what is that threshold?

[waterbear]

I got the idea that you shock a pool on a regular basis because the Pinch-a-Penny test results print-out says that that's one of the ABC's for a healthy pool -- you shock it once a week.
Yep, and they can sell shock that way on a regular basis. Works better for those that don't have salt pools but you get the idea. Pool stores are in the business of selling chems and things like shocking weekly and pushing phosphate removes (and selling "mineral systems") hellp increase their bottom line. Shocking once a week is really one of the ABCs of a healthy pool STORE since it increases their sales.

I'm intrigued that you and others don't do this, yet don't have troubles with your pool. I thought that over time the combined chlorine becomes a problem, so shocking weekly pretty much elminates any CC you have in the water? If you only shock when the CC reaches some threshold, what is that threshold?
If you have CC over .5 ppm then shock. If you keep the FC in line with the CYA level by keeping it at 5% of the CYA in a salt pool or following the Best Guess Chart (that I linked to above) then the fact of the matter is that you will basically not have CC. If you try and run your FC lower than this you will and will need to shock. Period. The correct FC for the CYA will keep einough 'active' chlorine in the water. Also, in a salt pool the water in the cell is being 'supershocked' to very high chlorine levels when the cell is on.

Trivia: for most people the 'threshold' where their nose can detect CC is .4 ppm.

[famousdavis]

Ahhhh, this site is so informative! What you're saying makes sense -- very good sense. I'm liking more and more the idea of keeping the pool at 4 PPM FC / 80 PPM CYA and do periodic testing for CC, shocking whenever it's necessary. If that happens just once a month, I'll likely opt to buy liquid chlorine and shock that way rather than use the Boost button on the salt cell. Not too much trouble, and the quickness of the liquid chlorine may be more effective than the 24-hour boost cycle. Avoiding weekly shocks saves $$$ and, with the right water chemistry, doesn't create a greater risk of algae, either. Very nice.

Our pool is getting a LOT of use this summer because 1) it's new, 2) there's 6 of us living in my home, 3) all 6 like to invite their friends over to swim. So I won't be surprised if I have to shock the pool somewhat frequently, but perhaps I don't need to do it weekly afterall, Pinch-a-Penny's advice be danged.

For the next few days, I'll leave the SWCG set at 50% for the pump's regular 8-hour cycle (I run the pump after the 8 hours if people are in the pool, but I don't switch on the SWCG). I want to see how quickly the FC is depleted with this setting. Once it reaches 4 PPM, I'll bump up the SWCG to 60% or 70% to try and get a net-zero change to the FC. I do have a variable-speed pump, so I certainly could run the pump longer and a lower speed if I need to.

It's been fun trying to figure out all this stuff. This forum has been a terrific source of knowledge, real-world experience and expert advice. I already know more about pool chemistry that several pool-owning friends who have owned pools for years and years!

[Watermom]

It's been fun trying to figure out all this stuff. This forum has been a terrific source of knowledge, real-world experience and expert advice. I already know more about pool chemistry that several pool-owning friends who have owned pools for years and years!

Because of what you've learned on the forum, you probably already know more about pool chemistry than the so called 'pros' who are testing your water for you at the pool store!

[famousdavis]

I think you're right! I certainly trust my own shaky judgment more now than the guy over at The Pool Store that uses a test strip to test my water. He's the fellow that sold me a $25 bottle of phosophates remover, causing my sparkly pool to turn cloudy, then gumming up my nearly-clean DE filter to the point I had to backwash it. I won't add that stuff in again! Wish I had read more deeply in this forum before I blindly followed his advice.

I don't over-estimate my knowledge -- I'm a pool chemistry neophyte still -- but I've got a reasonable handle on pool chemistry now, and a majority of what I've learned has come from this website and the little pamphlet that Taylor helpfully includes inside their K-2006 kit. I've hit a few other pool-related websites for information, too, but this site and the people in it have been by far the most helpful. The fact you have such active and knowledgeable moderators makes a huge difference. What I'm most pleased with is I've got a strategy for how I want to handle my pool maintenance duties that I've quickly developed, without having to go through a terribly long process of trial-and-error. I'm feeling pretty confident about keeping my pool clear and clean (and if I DO run into trouble, I'll come back to this forum to find some answers).

[Watermom]

I've hit a few other pool-related websites for information, too, but this site and the people in it have been by far the most helpful. The fact you have such active and knowledgeable moderators makes a huge difference.

Thank you!

[rpoldervaart]

and do periodic testing for CC, shocking whenever it's necessary. If that happens just once a month, I'll likely opt to buy liquid chlorine and shock that way rather than use the Boost button on the salt cell. Not too much trouble, and the quickness of the liquid chlorine may be more effective than the 24-hour boost cycle. Avoiding weekly shocks saves $$$ and, with the right water chemistry, doesn't create a greater risk of algae, either. Very nice.


You're starting to believe, but I don't think you're quite there yet. When Waterbear says you don't have to shock, you really don't have to shock; not even monthly. If you keep the FC and other chemicals where they should be, you shouldn't ever have to shock, unless something else happens.

I live in Houston with a SWCG and only throw in some bleach after a big pool party with my kid's friends, or when a hurricane brings through a bunch of dirty rain. If I got lazy and didn't check my pool for a while and saw the chlorine got low, I might through in a little bleach to bring it back up. I very rarely ever get any CC.

So if you keep a nice balanced pool, you won't have to "periodically" shock your pool. :cool:

Robert

[waterbear]

You're starting to believe, but I don't think you're quite there yet. When Waterbear says you don't have to shock, you really don't have to shock; not even monthly. If you keep the FC and other chemicals where they should be, you shouldn't ever have to shock, unless something else happens.


As it says in my sig "You can lead a pool owner to water, etc. etc. etc.":rolleyes::)

Don't worry, We've put the pod under his bed and when he awakes he will be one of us!:eek::eek::eek::cool:
(apologies to Keven McCarthy/Donald Southerland)

[BigTallGuy]

I just posted this in another thread about an hour ago. Please read.

Absolutely, You need Stabilizer. Here is a bit of a testimonial. Being a real card carrying "Big Tall Dumb Guy" with a SWCG, my scatter brain told me I didn't really care too much about the CYA (stabilizer) levels. So when I replaced my pool liner last year and installed a SWCG, I added some CYA but not enough. My Chlorine levels were good with my CYA at 25 - 30 PPM, AND ALL SEEMED GOOD.

After all, my chlorine is FREE, Right? Wrong! Chlorine isn't "free" when you have to run your pump twice as long to keep the Chlorine levels up (NOT TO MENTION BURNING OUT YOUR CELL).

I had to run my system for 7 hours a day to keep from running out of chlorine at sunset. I decided to stop being so stupid and I raised my CYA to 45 ppm and I am now running my pump for 4 hours a day. The $10.00 bottle of stabilizer will save me hundreds (Plural) yes hundreds of dollars in electricity.

You can learn a lot from a BIGTALLDUMBGUY!

[famousdavis]

"You're starting to believe, but I don't think you're quite there yet."

You're right. The proof (for me) will be how this forum's methodology holds up in *my* pool, right? But everyone here has convinced me that I don't have to blindly and ignorantly follow a local pool store's advice on how to care for my pool (for which I heartily thank you!). Moreover, you've raised an interesting, viable alternative that I'm willing to try -- keep up my CYA level, keep up my FC level, watch over my CC level, and shock only when the pool needs to be shocked. Doesn't have to be once a week. Doesn't have to be once a month, even. Just when I need it.

So, I'll give it a go. My "insurance policy" against algae, though, is that I'll still add a maintenance dose of polyquat each week. The relatively low cost of doing that gives me peace-of-mind. What I need to work out now is how much time the SWCG needs to operate to keep up the FC level. Over this week and next, I should be able to nail that answer down.

[Watermom]

Just an FYI (and somebody may have already told you this earlier in this thread -- I didn't take the time to re-read it) -------- polyquat will cause your FC to plummet. Then you'll have to add more chlorine to pull it back up.

[Flysurfn]

So, Cya of 30 and FC-1.5, running a SWCG/DE Filter 12hours a day on 50% isn't necessary?
I should raise CYA to 60 and FC of 3 with less time on the cell?

I must say this is a great forum...

[waterbear]

I just posted this in another thread about an hour ago. Please read.

I raised my CYA to 45 ppm

NOW raise it up to where it SHOULD be (around 80 ppm), drop you TA to 70 if it is higher than that, and start saving money on acid and maintenance and stop being a big tall dumb guy and become a big tall smart guy!:D

[waterbear]

So, Cya of 30 and FC-1.5, running a SWCG/DE Filter 12hours a day on 50% isn't necessary?
I should raise CYA to 60 and FC of 3 with less time on the cell?

I must say this is a great forum...

NO, you should raise it to 80 and maintain the FC at 4 ppm. The difference between 60 ppm and 80 ppm has been determined to be significant and directly translates into better pH stability in a salt pool.

[waterbear]

"You're starting to believe, but I don't think you're quite there yet."

You're right. The proof (for me) will be how this forum's methodology holds up in *my* pool, right? But everyone here has convinced me that I don't have to blindly and ignorantly follow a local pool store's advice on how to care for my pool (for which I heartily thank you!). Moreover, you've raised an interesting, viable alternative that I'm willing to try -- keep up my CYA level, keep up my FC level, watch over my CC level, and shock only when the pool needs to be shocked. Doesn't have to be once a week. Doesn't have to be once a month, even. Just when I need it.

You have just stumbled on to the secret on how commercial pools are maintained!

So, I'll give it a go. My "insurance policy" against algae, though, is that I'll still add a maintenance dose of polyquat each week. The relatively low cost of doing that gives me peace-of-mind. What I need to work out now is how much time the SWCG needs to operate to keep up the FC level. Over this week and next, I should be able to nail that answer down.

Adding borates to 50 ppm is a better insurance policy, only has to be done once and you don't need to worry about it until the level drops to 30 ppm (for most people this is once a year), and they also help keep the pH from rising as fast so your pH becomes even more stable.

[famousdavis]

Supermom said, "Just an FYI (and somebody may have already told you this earlier in this thread -- I didn't take the time to re-read it) -------- polyquat will cause your FC to plummet. Then you'll have to add more chlorine to pull it back up."

I had a dip in my FC after doing a maintenance dose of polyquat, but it didn't plummet:

FC on Tuesday morning (which followed a SWCG shock on Sunday-to-Monday): 7 PPM
FC this Wednesday morning (polyquat in the water 24 hrs): 5 PPM

And the drop may not be entirely the polyquat. I'm trying to figure out how long I need to run the SWCG, and I think it's set right now so I l lose a little FC each day (0.5 to 1 PPM).

Waterbear: I dumped 3.5lbs of stabilizer in the skimmer this evening after getting a 55 PPM reading from my CYA test. Great tip you gave on re-testing the CYA using the same water, btw. I tried three times just to make sure I got repeatable results (I did). I think my problem with my earlier CYA testing -- where I kept still seeing a little bit of the black dot, even after I added all 14ml into the tube -- was because I didn't wait long enough before pouring in the mixture. Taylor's instructions say wait at least 30 seconds, but waiting a couple of minutes is much better. Anyway, I'll take a reading tomorrow and see if my CYA level is up around 80 PPM. Then I'll continue leaving my SWCG settings alone (50% for 8 hours) and see what happens to my FC levels. Thanks so much for providing some clear advice on chemical levels!

[famousdavis]

*Apologies. Watermom + Super Moderator = Supermom.

[famousdavis]

So I tested my water today, 24hrs after adding more CYA in my pool. CYA is now 80. I tested my FC today, too. Instead of losing 0.5 or 1 PPM like I have been with my current settings (50% for 8hrs), my FC actually rose 0.5, to 5.0. And today was a full-sun kind of day, too!

I may tamp down my SWCG to 40% tomorrow and see what happens. I want to stay near the 4 PPM range.

I get my water tested by the two pool companies tomorrow, too. I can't wait to compare my results again with what their test results say! After tomorrow, I may just release the one company that uses test strips from doing my pool water analysis -- I think their test results are way screwy, especially with my TA and FC levels. Pinch-a-Penny's drop-based testing more closely aligns with my own testing, though last week they came up with a much lower FC level than what I came up with using the K-2006.

[famousdavis]

So I took two water sample from my pool this morning, gave one to The Pool Store (test strip testing) and one to Pinch-a-Penny (drop-based). Plus I did a few tests with my K-2006. Results:

FC
The Pool Store: 2.3
Pinch-a-Penny: 3.0
K-2006: 4.0

CC - everyone agrees, there is no CC

pH:
The Pool Store: 7.9
Pinch-a-Penny: 7.6
K-2006: 7.5 (yesterday's reading)

TA:
The Pool Store: 150
Pinch-a-Penny: 140
K-2006: 90

Ordinarly, The Pool Store has read way higher than Pinch-a-Penny, so I was surprised at today's high TA from Pinch-a-Penny. I was also surprised at their recommendation: that I add 1.3 gallons of muriatic acid into my pool! However, I watched closely the testing process at Pinch-a-Penny this morning. The gal had to run the test twice because the first time her TA reading was, I guess, astonishingly high. During the second test, the reagent she added that turned the water from green to pink resulted in only a slighly higher reading than the "Ideal" markings on her big test tube that measured the amount of reagent she was adding (Pinch-a-Penny says "Ideal" is between 80 and 120). Clearly, there was an imprecise testing process at work that led to the wide discrepancy between her two tests! And even though her second test showed high TA, I did notice that she tended to add a few more drops of reagent even after the water turned from green to pinkish-red. After her high reading, I went home and re-tested TA using my K-2006. I noticed that when I test, I do so MUCH more slowly and deliberately. And I stop immediately after the water turns from green to pink color (the 9th drop of reagent changes a blood red color to pink). Pinch-a-Penny uses Taylor reagents, too, but their setup is different where they measure reagent from a test tube that they're adding to the swirling water, whereas I am counting drops of reagent. I think the speed with which they perform their test compared to my own testing explains the differences in our results. I'm also confident that my reading is correct because I used their last week's TA reading (80) which also matched the K-2006 reading for last week to add just enough baking soda to get to about 90-100 PPM (this was before Waterbear's advice to keep the TA at the low end of "Ideal").

CH:
The Pool Store: 300
Pinch-a-Penny: 350
(I didn't test this since it's been stable since I got our pool)

CYA:
The Pool Store: 75
Pinch-a-Penny: 80
K-2006: 80

CONCLUSION: I think I can now test my own water using the K-2006 as well as the "pros" at Pinch-a-Penny, and I can do a decidedly better job of testing my own water than the test-strip folks at The Pool Store. So I'll "fire" The Pool Store and move to less frequent visits at Pinch-a-Penny, just to ensure I maintain the warranty requirements on my Diamond Brite finish. And I'll trust my own judgment -- and the judgment of this forum -- more than the advice I get from Pinch-a-Penny.

A BIG THANK YOU to this forum! I feel like a Pool School graduate today. :-)

[BigTallGuy]

NOW raise it up to where it SHOULD be (around 80 ppm), drop you TA to 70 if it is higher than that, and start saving money on acid and maintenance and stop being a big tall dumb guy and become a big tall smart guy!:D

I ordered my Taylor K2006 test kit via Ben's link and I am waiting for it to arrive so I can do proper testing. You may remember that I had an extremely bad experience with CYA a few years ago and I would like to know who sets the 80 PPM standard for SWCG Pools, and why.

My SWCG owner's manual says 50 PPM of CYA, and I believe I read one of ChemGeek's post that says the higher above 50 you get the CYA, the more it actually counter acts with chlorine. In addition, I still need to run my filter at least 4 hours a day for a good turn over.

SO HERE IS MY QUESTION TO ANY AND ALL POOL OWNERS WITH A SWCG THAT KEEP THEIR CYA AT 80 PPM AND THEIR CHLORINE AT 4.0 OR HIGHER, DO YOU EXPERIENCE OR GET COMPLAINTS ABOUT BURNING EYES? BE HONEST, BECAUSE THAT WAS MY EXPERIENCE.

[waterbear]

I ordered my Taylor K2006 test kit via Ben's link and I am waiting for it to arrive so I can do proper testing. You may remember that I had an extremely bad experience with CYA a few years ago and I would like to know who sets the 80 PPM standard for SWCG Pools, and why.
The manufactuers and for some of them it's as high as 100 ppm such as for the unit you have. Actually, a lot of it came from discussions on here and on TFP and chem geek is an integral parto of it. It came from the range that SWCG manufactuers recommended and it is the upper limit for most of them (Some units, set the upper limit at 100 and Penair sets it at 85. I don't know of any that set the upper limit at 50 ppm btw.) It was determined that SWCGs operated most efficiently at the upper limit of CYA and had the best pH stability.
My SWCG owner's manual says 50 PPM of CYA, and I believe I read one of ChemGeek's post that says the higher above 50 you get the CYA, the more it actually counter acts with chlorine. In addition, I still need to run my filter at least 4 hours a day for a good turn over.
No, I think you have that confused. There is evidence that above 60 ppm CYA has a direct UV blocking effect in water. Chem geek wrote quite a bit on that either here or at TFP, I can't remember which.
Also, if I remember correctly you have a compupool CPSC-24 which has a MINIMUM CYA level of 40-60 ppm and a MAXIMUM level of 100 ppm (as do many of the Australian units) so your CYA should be at 100 ppm and your FC at 5 ppm. When you posted about burning eyes your CYA was at 50 ppm and your FC at 5.
SO HERE IS MY QUESTION TO ANY AND ALL POOL OWNERS WITH A SWCG THAT KEEP THEIR CYA AT 80 PPM AND THEIR CHLORINE AT 4.0 OR HIGHER, DO YOU EXPERIENCE OR GET COMPLAINTS ABOUT BURNING EYES? BE HONEST, BECAUSE THAT WAS MY EXPERIENCE.
I have never known CYA to cause burning eyes (and my own has been at 80 ppm for several years now). pH problems can cause burning eyes. Chloramines can cause burning eyes (and with high CYA and bad pool management it is very possible to have persistent chloramines.)

YOUR CYA should be at 100 ppm. If you don't believe me look on your manual on the first page after the table of contents where it says at the bottom that CYA should be maintained at 40-100 ppm and that 40-60 ppm is the MINIMUM where it should be maintained. I have explained many times WHY higher CYA is beneficial in a salt pool (and for that matter it is often beneficial in a non salt pool, as Ben and the mods can tell you also.)

When you posted problems of eye irritation it is very possible that your FC was very high since you said it was 5+ and you did not have a test kit capable of testing high chlorine levels (or FC for taht matter so it is possible that you also had chloramines present and that would explain the eye irritation.)

Bottom line, it's your pool and you can do what you want but if you want ot minimize the problems associated with salt pools and save money then raising your CYA to 100 ppm is in your best interest.

I realize that you are very slow to take the advice here since you just now ordered a good test kit even though it's been recommended to you for quite some time. I understand that you have a problem with an overstabilized pool in the past (I suspect you were using trichlor at the time) but to try and correlate that experiece with managing a salt pool is comparing appels and oranges. High levels of CYA are not intrinsicially bad or evil but many seem to think so. In acutallity, CYA is the best thing that every happened to outdoor pools. Stabilized chlorine, on the other hand, can be problematic since it continaully causes CYA to rise to levels high enough to cause problems.

[famousdavis]

Just an epilogue to yesterday's "pro" water testing and my own K-2006 test results. Yesterday I tested my TA after The Pool Store said I had a TA of 150 and Pinch-a-Penny said my TA was 140 (and who also said I should dump a LOT of muriatic acid in to bring down the TA). My K-2006 said I had a TA of 90. My OTO test kit also had a TA test I could perform, and it said I had a TA of 90.

So today I took another water sample (without having done anything to my water since yesterday) to a different Pinch-a-Penny on the southside of my town. Guess what? According to them, my TA was *too low* (75) and I was supposed to add alkalinity increaser to my pool!

What a bunch of bologne!

In the cases of drop-based Pinch-a-Penny, I observe them *hurriedly* working through their various tests, and that leads, I believe, to a lot of imprecision when it comes to rinsing out their tubes and correctly measuring the amount of water they poor into their tubes and jars. For one Pinch-a-Penny to test my TA at almost one-half of what the other Pinch-a-Penny determined is just plain ludicrous.

How happy I am that I can do my own water testing, saving me from regular weekly trips to the pool stores! I'm going to save a TON of money doing my own testing and carefully adding *only what's needed* to my pool, rather than blindly following the "expert" advice of the pool stores!

[waterbear]

NOW you are catching on to why we say to test the water yourself with a good test kit!

[BigTallGuy]

Thanks Evan. I appreciate your reply. I am embarrased, and publically admit you were right about the CYA. I must have read the Pool Info, Not the SWCG info. Please accept my apologies.

In my case a few years ago, the Problem with the CYA was on a Fresh fill. I drained my pool to less than 1 inch of water and refilled. After adding the CYA, and discovered the "high CYA Problem", I had the water tested at three different pool stores (before I ever heard of this Forum) and not one could find anything wrong with my pool chemistry. The unanimous consensus was high CYA as the cause of the eye irritation. I cannot explain how 4 Lbs. of CYA took me to readings in excess of 110 PPM in approximately 11,000 gallons of water, nor can I explain why draining 2/3 of the pool water (the following year) and refilling with fresh water took me to 100 ppm. But that pool and all its water and problems are long gone, so it will remain a mystery.

Yes I am a slow learner, I don't just go out and buy or do everything everyone tells me to until I investigate it. After all when your own children and grandchildren tell you that their eyes burn in your pool, I will err on the the side of caution. As far as the test kit is concerned, my old one was barely adequate, but wouldn't test CYA, so yes, I ordered the Taylor.

Thanks again Evan, and Peace.

Rick.

[waterbear]

Thanks Evan. I appreciate your reply. I am embarrased, and publically admit you were right about the CYA. I must have read the Pool Info, Not the SWCG info. Please accept my apologies.

In my case a few years ago, the Problem with the CYA was on a Fresh fill. I drained my pool to less than 1 inch of water and refilled. After adding the CYA, and discovered the "high CYA Problem", I had the water tested at three different pool stores (before I ever heard of this Forum) and not one could find anything wrong with my pool chemistry. The unanimous consensus was high CYA as the cause of the eye irritation. I cannot explain how 4 Lbs. of CYA took me to readings in excess of 110 PPM in approximately 11,000 gallons of water, nor can I explain why draining 2/3 of the pool water (the following year) and refilling with fresh water took me to 100 ppm. But that pool and all its water and problems are long gone, so it will remain a mystery.
No mystery at all. I have seen it many times. When CYA levels are very hiigh for an extended period of time CYA tends to deposit in the plumbimg and pool surfaces and when you refill it residdolves and brings the level higher than you expect. As far as the pool store folk not knowing why the water was making burning eyes...well, since I used to work in a pool store I don't have a lot of respect for a lot of people that work in them, 'nuff said?:rolleyes:

Yes I am a slow learner, I don't just go out and buy or do everything everyone tells me to until I investigate it. After all when your own children and grandchildren tell you that their eyes burn in your pool, I will err on the the side of caution.
But how do you know which way to err? Less is not always best (as the best guess chart shows with chlorine levels!)
Hypothetical point, If there were burning eyes and the pool store said that everything was fine (because their testing method bleached out at high chlorine levels and could not detect the combined chlorine in the water--actually, I have seen this happen--and someone else said to add more chloirne to get rid of the burning eyes but your chlorine was already high (and your CYA was high). would you give it a try to see if it worked? I believe you know enough about pool chemistry now to know it would!

As far as the test kit is concerned, my old one was barely adequate, but wouldn't test CYA, so yes, I ordered the Taylor.


Have you received the Taylor kit yet? I think you will find there is a BIG difference between 'barely adequate' and a good test kit. If I remember right your old test kit was OTO and not DPD. There is a reason that the Taylor kit is recommended, otherwise we would probably recommend getting a cheap '5-way' kit from Ace Hardware and adding a CYA test to it. The end result is so different it is a case of apples and oranges!

[famousdavis]

NOW you are catching on to why we say to test the water yourself with a good test kit!

Yes, I've caught on, alright. I'll happily sing the praises of self-testing one's own pool water to whoever will listen to me. I've got a friend at work who just bought a house with a pool (he's a first-time pool owner now), and I'm anxious to show him my recent "pro" test results to emphasize the point he should test his own water, rather than relying on his pool service or a nearby Leslie's pool store.

[BigTallGuy]

Have you received the Taylor kit yet? I think you will find there is a BIG difference between 'barely adequate' and a good test kit. If I remember right your old test kit was OTO and not DPD. There is a reason that the Taylor kit is recommended, otherwise we would probably recommend getting a cheap '5-way' kit from Ace Hardware and adding a CYA test to it. The end result is so different it is a case of apples and oranges!

Not yet. I am expecting it this week. I am looking forward to working with this kit when it arrives.

Yes, barely adequate vs. good, I'm sure is miles apart. But for the record, since May, 2010, when I converted to Salt along with a new liner and fresh water, My pool has been sparkling clean, without a single algae bloom or "green" day, and no burning eyes (thanks to many people on this Forum) I only have had to add bleach one time. All with my old test kit and a few tests at the pool store. So justifying the $57 for a Taylor kit was a little rough. My last bout with the CYA levels (different Thread) was the last straw.

The residual CYA in the liner, plumbing etc. was suggested before and is the only thing that makes sense, as it would be chemically impossible to repeat the readings with 4 Lbs. of CYA. I didn't know until now if this was a real possibility or a theory. Thanks for clearing that up.

[PoolDoc]

I can't see any way you could stow 4# of dissolved CYA in the liner and pipes. Not sure who suggested that, but unless it was Chem_Geek, I'd forget about it. If it WAS Chem_Geek, I've got a bunch of questions for him.

Ben

[chem geek]

BigTallDumbGuy was referring to waterbear's post (http://www.poolforum.com/pf2/showthread.php?13347-Jandy-SWCG-s-quot-optimal-quot-water-conditions-why-raise-CYA&p=80565#post80565) where he wrote "When CYA levels are very hiigh for an extended period of time CYA tends to deposit in the plumbimg and pool surfaces and when you refill it residdolves and brings the level higher than you expect." I have heard that before in the context of there being a small amount of residual CYA reading in spite of pools being drained. However, 4 pounds of CYA in 11,000 gallons is 44 ppm and that's much higher than the kind of residual that can be left over. Since a proper test kit was never used in the pool being described that had CYA in it, I don't think it's worth spending any time trying to figure it out.

[BigTallGuy]

I agree Chemgeek, it is not worth trying to figure out. As I stated, that pool and its issues are long gone. However, there are 3 facts to consider.

1, Multiple vanishing black dot tests were performed at 3 different pool stores, and I'm sorry but I can't believe ALL of the tests were faulty tests. In all total, at least 6 different test were performed (2 per store). I asked each of the people performing the tests to be very careful with their testing. My CYA was over 100, way over.

2, High CYA readings (over 100) are reportedly difficult to read unless you do a little fancy dilution with distilled water, which none of the pool stores did.

3, I bought a 6 Lb. bottle and took the remaining unused CYA back to the pool store and had it weighed. with the bottle, there was 2.1 Lbs of unused CYA left over out of the original 6 Lbs. So I can say it with a pretty high degree of accuracy that 4 Lbs. was all I put in.

[waterbear]

1, Multiple vanishing black dot tests were performed at 3 different pool stores, and I'm sorry but I can't believe ALL of the tests were faulty tests. In all total, at least 6 different test were performed (2 per store). I asked each of the people performing the tests to be very careful with their testing. My CYA was over 100, way over.

2, High CYA readings (over 100) are reportedly difficult to read unless you do a little fancy dilution with distilled water, which none of the pool stores did.

.

And there you have it. It is IMPOSSIBLE to know how much over 100 it is without diluting and with dilution you lose precision. The CYA level might have been MUCH higher than thought. Many people, including pool store employees do not understand what precision means in water testing. Ben used to have a very good explanation page on PoolSolutions but it does not seem to be there anymore.

[rpoldervaart]

SO HERE IS MY QUESTION TO ANY AND ALL POOL OWNERS WITH A SWCG THAT KEEP THEIR CYA AT 80 PPM AND THEIR CHLORINE AT 4.0 OR HIGHER, DO YOU EXPERIENCE OR GET COMPLAINTS ABOUT BURNING EYES? BE HONEST, BECAUSE THAT WAS MY EXPERIENCE.

I don't feel any burning. If my son swims in our pool, he'll have pretty clear eyes later on. He came home the other day after swimming in a public pool and his eyes were bright red. I have no idea what the chemicals were like in the public pool.

[famousdavis]

I don't feel any burning. If my son swims in our pool, he'll have pretty clear eyes later on. He came home the other day after swimming in a public pool and his eyes were bright red. I have no idea what the chemicals were like in the public pool.

I'll second rpoldervaart's observation that a high CYA pool and free chlorine >= 4.0 doesn't lead to burning eyes. It's been a little over a week now since I upped our pool's CYA to 80, but in that time no one has complained about burning eyes. We swam after I used the Boost button on our SWCG, and so even swimming in a pool that had FC = 12.5 didn't lead to burning eyes or any eye irritation at all. I'd say we've had about 10 different people swimming in these conditions -- adults, teens, young children -- and not a problem at all.

But everyone's eyes are different, so what works for most people's eyes may not work for a few others.

[BigTallGuy]

Thanks to all that responded. Famousdavis, I sincerely apologise for trashing your thread.