Is stabilizer necessary?

[JimK]

I was reading this link ( http://www.truetex.com/poolcontrol.htm#cyanurics ), and the section titled "Eliminating Cyanurics" caught my attention. According to this article, stabilizer isn't needed and in fact makes it much more difficult to sanitize the pool and extremely difficult/impossible to kill algae without having to shock on a regular basis.

He states he does not use stabilizer and can sanitize/kill algae with far lower free chlorine levels (well less than 1ppm; I think he mentions .2ppm or so). It seems unstabilized chlorine is extremely effective even at low levels.

Has anyone tried this method? Can it be done when using a SWG (mine recommends CYA at 60-80, would a CYA level of 0 hurt it?)?

I understand CYA prevents UV from depleting the chlorine quickly, but also greatly reduces its effectiveness. Would a SWG be able to keep up with demand without using any CYA or prematurely depleting the cell?

Seems like this method could save quite a bit of $$. Any thoughts/experience with this are greatly appreciated.

[BigDave]

Yes, it is in an outdoor pool. Please read through this thread (http://www.poolforum.com/pf2/showthread.php?10303-Cyanurics) which contains a discussion of the need for stabilizer.

I've read the pool automation website and I think it's a pretty neat project but essentially misguided.

Feel free to post back here after looking over the thread above if you have any questions or if something is unclear, I didn't reread the entire thread today so...

[JimK]

Thanks for the link.

I read through that thread but was left even more confused. I really didn't see anything in that thread that discussed the need/benefits for using CYA and why it's better to use it than not. The focus of the thread seems to be on Kent Williams and the disagreement with his recommendations and how some here do not like him. But the link I posted was written by Richard Kinch. In the thread you mentioned Ben/PoolDoc says this:

"...Richard knows more about the chemical relationships among chlorinated cyanurates in pools than anyone I know . . "

Is he talking about the same Richard? If so, then I'm really confused as Richard seems to be advocating not using CYA.

As I'm certainly FAR from being and expert (just a pool owner who's trying to learn how properly to take care my pool without wasting a bunch of time and money on it) I would greatly appreciate some guidance and clarity.

Thanks.

PS - If it matters, I have an outdoor IG 20k gal. vinyl pool with an Aquarite SWG and Hayward DE6020 DE filter.

[BigDave]

Jim,
I'm sorry, I didn't choose the best example in the thread I referenced. My bad. There are better discussions here on Pool Forum.
The important thing to understand is: in a stabilized pool, more chlorine is available where it needs to be to destroy pathogens that enter the water.
Stabilizer binds a percentage (a large percentage but not all) of the Free Chlorine, this protects the chlorine from the sun but also prevents it from sanitizing the water. This applies only to the bound chlorine which is a portion of the Free chlorine. When the portion of the unbound chlorine is used up reducing some "dirt" that gets in the pool, the stabilizer releases bound chlorine to become unbound chlorine and maintain the portion of unbound chlorine to bound chlorine. This newly unbound chlorine is immediately available to attack more "dirt" in the place where the dirt is.
On the other hand, in a pool with no stabilizer, all the Free Chlorine is available to attack the "dirt" but when the supply of chlorine in the immediate vicintity of the "dirt" is exhausted, the remaining "dirt" won't be sanitized until circulation and dispersion bring more chlorine close enough to it.

[JimK]

Thanks Dave. That information is helpful. So bottom line, I should stick with the CYA levels recommended by the manufacturer of my SWG?

Some info for reference.....

One reason this topic caught my attention is my personal experience over the past several years dealing with algae in my pool (my pool was installed in the spring of 2004 and it's the only pool I've ever owned). It seems despite keeping CYA in the 60-80 range, FC 5-7, and PH 7.5-7.6, the liner would keep getting slick (start of an algae breakout?) and I would have to shock and brush the pool frequently. Based on a recommendation a few years ago, I started using borax (maintained at 40-50) and polyquat 60 (I add a maintenance dose of 8 oz per week). Since doing this in combination of shocking every couple of weeks, I no longer have an issue with a slick liner. However, I do still get some visible algae in grooves and crevices (such as where the liner meets the steps and behind the trim around the pool light; possibly due to poor circulation in those areas?) which I'll brush out before my regular shock treatment.

I'm tempted to discontinue the polyquat 60 to see what happens. That would save me a couple hundred dollars a season, but I'm hesitate to mess with what's currently working well for me. Except for the addition of polyquat 60 and Jack's Magic Purple Stuff (since using this I have no more staining issues which I'm told is a side effect of the SWG), I pretty much follow the BBB method.

BTW, except for a few spring openings when I was using a mesh cover over the winter (I use a solid cover now), my pool have never been green (during the season it's always clear).

[Watermom]

Yes, stick with the CYA levels recommended by your SWCG manufacturer. And, not the same Richard. "Our" Richard is "ChemGeek" who is a valuable member here on PF.

[JimK]

So not the same Richard, that makes much more sense.

While you were posting, I was editing my post. Any comments on the info I've added?

Thanks.

[Watermom]

Go ahead and try it without the Polyquat and just be diligent about keeping up with your chemistry. You can always go back to using it if you decide you need to. I never use any Polyquat, not even when closing my pool. I'm consistent about my chemistry and don't really need it. What I don't have to spend on that, I can use to buy something else like maybe dog food! My 3 golden retrievers go through LOTS of dog food!

[JimK]

Go ahead and try it without the Polyquat and just be diligent about keeping up with your chemistry. You can always go back to using it if you decide you need to. I never use any Polyquat, not even when closing my pool. I'm consistent about my chemistry and don't really need it. What I don't have to spend on that, I can use to buy something else like maybe dog food! My 3 golden retrievers go through LOTS of dog food!

Thanks for the response. When I'm feeling brave and ready to experiment (lol), I'll give it a shot.

[waterbear]

The article you reference is using ORP controllers to monitor the redox potential of the water (and not directly monitoring FC levels) and using a liquid chlorine injection system. First fact, CYA disrupts ORP controllers so systems that use then do not use CYA (or use very reduced levels). Second, his system has a pretty much constant chlorine 'drip" going into the pool. This is how many commercial systems are run out of necessity but it is not necessisarily the best way. I have also worked on a commercial install that used peristaltic dosing pumps for both liquid chlorine and acid for pH control but did not have any electronic control. The 2 pools and two spas at this installation were tested 3 times a day and the dosing pumps adjusted if needed. However, once they were set up they needed very little adjustment to keep everything where it was supposed to be.
The info he references in the article (including teh one from Kent Williams) are mostly from those with connections to ORP controller manufacturers so it is in their best interest to say that CYA is NOT beneficial because when you use ORP control it is a problem and makes the system malfunction.

[waterbear]

One reason this topic caught my attention is my personal experience over the past several years dealing with algae in my pool (my pool was installed in the spring of 2004 and it's the only pool I've ever owned). It seems despite keeping CYA in the 60-80 range, FC 5-7, and PH 7.5-7.6, the liner would keep getting slick (start of an algae breakout?) and I would have to shock and brush the pool frequently. Based on a recommendation a few years ago, I started using borax (maintained at 40-50) and polyquat 60 (I add a maintenance dose of 8 oz per week). Since doing this in combination of shocking every couple of weeks, I no longer have an issue with a slick liner. However, I do still get some visible algae in grooves and crevices (such as where the liner meets the steps and behind the trim around the pool light; possibly due to poor circulation in those areas?) which I'll brush out before my regular shock treatment.

I'm tempted to discontinue the polyquat 60 to see what happens. That would save me a couple hundred dollars a season, but I'm hesitate to mess with what's currently working well for me. Except for the addition of polyquat 60 and Jack's Magic Purple Stuff (since using this I have no more staining issues which I'm told is a side effect of the SWG), I pretty much follow the BBB method.

BTW, except for a few spring openings when I was using a mesh cover over the winter (I use a solid cover now), my pool have never been green (during the season it's always clear).

Sounds like a circulation problem, although I have another suspicion as to what might be going on and adding to the problem. A few questions:
How many hours do you run the pump a day?
One speed or two speed pump?
How many returns, skimmers, etc?
Which cell are you using with your Aquarite, T-3, T-9, or T-15?
What output percentage is the Aquarite normally set on?
What are you using to test the water and how often do you test?
How often do you brush your pool?
Do you have an automatic pool cleaner? If so which one and how often do you run it?
How often do you vacuum your pool?
How often do you backwash the filter and do you retest the water after topping it off and adjust chemical levels again if needed?
What are you shocking with (the SWCG or with manual addition of a chemical) and it is after or before backwashing?

FWIW, you should run your CYA at 80 ppm with the AquaRite. I indirectly helps with pH control since you can run the cell at a lower output to maintain the same FC which means less production of hydrogen bubbles in the cell which means less aeration of the water which means less outgassing of CO2 and outgassing of CO2 is the main cause of pH rise in a pool.

Using both borate at 50 ppm and polyquat is probably overkill and personally I am a big fan of borate and have actively promoted its use for several years now.

Getting back to your pool problem...IF you have pool circulation in some areas then algae might start growing even if you are doing everything right. Running with no CYA is NOT going to solve the problem and could even make it worse. The best way to solve the problem is to brush the pool on a regular basis. You want to brush down the sides of the pool all the way around. This sets up currents that 'stir up' the water in the pool and help eliminate dead spots. Most people do not brush their pools often enough, many do not brush the entire pool but only areas that have algae or dirt, and some pools just need more brushing than others to keep them clean.

[JimK]

Sounds like a circulation problem,

It's really not much of a problem, mainly a minor annoyance, as I only see algae in a couple small spots in crevices where it's likely water circulation isn't great. The rest of the pool stays clean, clear and free of algae.


How many hours do you run the pump a day?

14 hrs a day (it's on a timer; runs from 7am to 9pm)


One speed or two speed pump?

Single speed pump (Hayward Superpump; not sure of the HP rating but I'll check tonight)


How many returns, skimmers, etc?

2 skimmers, 3 returns (one of which is in the steps)


Which cell are you using with your Aquarite, T-3, T-9, or T-15?

T-15


What output percentage is the Aquarite normally set on?

Normally 40-50%


What are you using to test the water and how often do you test?

For PH, TA, CYA I use a Taylor test kit/reagents. For Chlorine, I use the Taylor DPD powder test kit. For borates I use LaMotte test strips. This year I just started using the test strips recommended here to test salt level (matches almost exactly the reading I'm getting on my SWG). After everything is balanced and up and running, I usually test PH and Free Chlorine every other day (if I notice a significant change or something going on, then I'll test everyday or more often until back on track). TA usually gets tested about every 10 days to 2 weeks (again, if needed, I'll adjust and test more frequently). I'll test CYA, borates, and salt if the salt level reading on the SWG drops. For some reason I feel like I'm forgetting something here (I'm at work right now and trying to do this from memory). I'll check my records (I keep a pool calendar/diary) when I get home to see if I forgot something.


How often do you brush your pool?

Once up and running/balanced, not very often as it doesn't seem to need it. Like I mentioned before, since using borates and Polyquat 60 I never have a slick liner or visible algae (except in a couple crevices as mentioned above).


Do you have an automatic pool cleaner? If so which one and how often do you run it?

Yes. Up until this year, I was using a Hayward Viper (uses a booster pump). The Viper died again so this season I replaced it with a Polaris 280 (also uses a booster pump; works great so far, better than the Viper IMO). I would say on average I run it every other day (I like to keep my pool clean and pretty)


How often do you vacuum your pool?

I manually vaccuum for spring cleanup, then infrequently during the season as the automatic cleaner does a good job keeping it clean.


How often do you backwash the filter and do you retest the water after topping it off and adjust chemical levels again if needed?

Whenever the pressure rises 10lbs above "clean" pressure (clean pressure is typically 10lbs, so when it gets close to 20lbs I'll backwash). Usually during the entire season I only have to backwash once or twice (I'm using a Hayward DE6020 DE filter).


What are you shocking with (the SWCG or with manual addition of a chemical) and it is after or before backwashing?

Since replacing the salt cell in 2006, I stopped using the SWG to shock (ie - set to "superchlorinate"). I figured manually shocking with Calcium Hypochlorite (68% is what I use. I'll have to double check the chemical name when I get home, but I believe this is correct) I could extend the life of the new cell. Our pool gets light use (only two of us in the household) and I find shocking every 2 weeks seems sufficient (unless we get a very heavy rain at which time I'll go ahead and shock again). There's no correlation between when I backwash and when I shock.


FWIW, you should run your CYA at 80 ppm with the AquaRite. I indirectly helps with pH control since you can run the cell at a lower output to maintain the same FC which means less production of hydrogen bubbles in the cell which means less aeration of the water which means less outgassing of CO2 and outgassing of CO2 is the main cause of pH rise in a pool.

Using both borate at 50 ppm and polyquat is probably overkill and personally I am a big fan of borate and have actively promoted its use for several years now.

Getting back to your pool problem...IF you have pool circulation in some areas then algae might start growing even if you are doing everything right. Running with no CYA is NOT going to solve the problem and could even make it worse. The best way to solve the problem is to brush the pool on a regular basis. You want to brush down the sides of the pool all the way around. This sets up currents that 'stir up' the water in the pool and help eliminate dead spots. Most people do not brush their pools often enough, many do not brush the entire pool but only areas that have algae or dirt, and some pools just need more brushing than others to keep them clean.

Thanks for your help and info.

Overall my current routine works very well, I'm just wondering if I'm overdoing it with the algae control and perhaps can save some money.

[JimK]

The article you reference is using ORP controllers to monitor the redox potential of the water (and not directly monitoring FC levels) and using a liquid chlorine injection system. First fact, CYA disrupts ORP controllers so systems that use then do not use CYA (or use very reduced levels). Second, his system has a pretty much constant chlorine 'drip" going into the pool. This is how many commercial systems are run out of necessity but it is not necessisarily the best way. I have also worked on a commercial install that used peristaltic dosing pumps for both liquid chlorine and acid for pH control but did not have any electronic control. The 2 pools and two spas at this installation were tested 3 times a day and the dosing pumps adjusted if needed. However, once they were set up they needed very little adjustment to keep everything where it was supposed to be.
The info he references in the article (including teh one from Kent Williams) are mostly from those with connections to ORP controller manufacturers so it is in their best interest to say that CYA is NOT beneficial because when you use ORP control it is a problem and makes the system malfunction.

Thanks. I appreciate the clarification.

[JimK]

Hmmmm......for some reason I can't edit my post. Anyway, if it matters, my Hayward Superpump is 1hp.

Again, comments and suggestions are most welcome.

[waterbear]

My advice is just keep up the borate, stop the polyquat, and brush more. It's good that you have a pressure side cleaner since they act as as moving 'return' and help improve circulation. Running it it bit more often or a bit longer might be helpful but your electricity useage will go up.:eek:Brusihing the pool more often is cheaper!;)

[JimK]

My advice is just keep up the borate, stop the polyquat, and brush more. It's good that you have a pressure side cleaner since they act as as moving 'return' and help improve circulation. Running it it bit more often or a bit longer might be helpful but your electricity useage will go up.:eek:Brusihing the pool more often is cheaper!;)

Thanks for the tips.

Brush more? ugh! I'd rather pay for the electricity to run the cleaner more often. Can you tell I just "love" brushing (LOL)?

[waterbear]

Thanks for the tips.

Brush more? ugh! I'd rather pay for the electricity to run the cleaner more often. Can you tell I just "love" brushing (LOL)?

Pools are like teeth. If you don't brush them enough they can get yucky.;)
In both cases brushing helps break up biofilms! In your mouth it's called plaque. On your liner it's what makes it feel 'slimy'. The chlorine in your pool is like an antiseptic mouthwash. It kills germs (algae) but doesn't do much against plaque (biofilm) without brushing and flossing.;)

[JimK]

Pools are like teeth. If you don't brush them enough they can get yucky.;)
In both cases brushing helps break up biofilms! In your mouth it's called plaque. On your liner it's what makes it feel 'slimy'. The chlorine in your pool is like an antiseptic mouthwash. It kills germs (algae) but doesn't do much against plaque (biofilm) without brushing and flossing.;)

Hehehe......good one. My mother is a Dental Hygienist so I know exactly what you are talking about! She made dang sure all us kids developed good brushing/flossing habits.

Hmmm.....since adding borates and polyquat to my routine several seasons ago, I never get a slick liner. Perhaps my automatic cleaner has been taking care of the "brushing" for me?

I promise I'll try to do better, Mom. (LOL!)

[PBLsQuad450]

There is a part of this thread that doesn't make sense to me. It's me of course, but here is what I don't get... Once Cl is in solution it is like milk in your coffee right? No part of the inside of your coffee mug is in contact with a differing level of milk. (yes, beneath the water line) Not even in the crevice where the base meets the side cylinder walls. If circulation is being considered as a potential reason (and I get this is theoretical at this point as other additives are attending to the algae relapses) for small algae relapses then the CYA would have to be near zero and the pool in full sun right? That would account for the drastic loss of Cl as it is being produced and disappearing almost simultaneously and therefore not reaching certain areas? If the Cl is in solution and staying around even for just a visit, it should be in contact with all surfaces equally? Instead of using additional products why not just use more Cl and a higher CYA level? Using the chart provided, keep the Cl level slightly higher? It has to be cheaper and easier than adding two additional chemicals.

Anyway, just thinking...

[waterbear]

However, unlike the milk in your coffee it does not get "used up". If there are areas of poor circulation it is very possible for there to be localized areas where the chloirne is "used up" which can allow algae to grow. Running higher FC is not really going to solve circulation problems. More frequent brushing can help. These are essentially 'stagnant" areas where chemicals like chlorine can become depleted and no new reserse is carried in fast enough to prevent problems.

[chem geek]

And technically the flow rate of circulating water goes to zero at surfaces. Water and chemicals get to surfaces via diffusion while circulation has more to do with the size of that diffusion layer and therefore the net rate of diffusion through that layer. This is why brushing the pool is still important even with proper chlorine levels, especially with plaster or other somewhat "rough" surfaces.

In practice, we don't see pool surfaces in most pools properly maintained getting slimy or having noticeable biofilm with the possible exception of just above the waterline on tile or in spas and above the water in skimmer baskets, etc. That's why the question was asked about circulation and why brushing is still recommended.

[PBLsQuad450]

"The important thing to understand is: in a stabilized pool, more chlorine is available where it needs to be to destroy pathogens that enter the water."

does this mean that where Cl destroys "dirt" it leaves behind a Cl free void? The Cl is in suspension operating in a liquid? so, if a piece of "dirt" falls from the sky into the pool does it leave a Cl free trail on it's decent to the bottom of the pool? And when it lands does it have a Cl free zone around it because it exhausted the Cl in it's immediate contact? If so, how long does that Cl free zone last? Long enough for algae to develop?

"And technically the flow rate of circulating water goes to zero at surfaces. Water and chemicals get to surfaces via diffusion while circulation has more to do with the size of that diffusion layer and therefore the net rate of diffusion through that layer. This is why brushing the pool is still important even with proper chlorine levels, especially with plaster or other somewhat "rough" surfaces."

Is this considering the sides and floor beneath the water line "surfaces?" The OP indicated his
blooms were in crevices at the base of his stairs and the like, not where surface tension inhibits circulation? I am dense so pardon me, but where the OP indicates he operates at 60-80ppm CYA and 5-7ppm Cl why wouldn't 80-85/90 CYA and 8-11ppm Cl fix that? I almost NEVER shock, just once all of last season after a hurricane, so like never. I must be dumb lucky. I'm counting my blessings and going swimming! Recurring algae blooms would make me nuts. I just knocked wood of course...

[BigDave]

does this mean that where Cl destroys "dirt" it leaves behind a Cl free void? Yes; in a pool without stabilizer. If there is chlorine in the immediate vicinity bound to stabilizer then when the unbound chlorine is used up, chlorine is released by the stabilizer and is available right where it's needed.

[chem geek]

Chlorine that is bound to CYA is released very quickly where half can be released in 0.25 seconds. And yes, you are right that the bigger problems tend to be in corners or other areas where circulation is particularly poor (and yes, by surfaces I mean all solid surfaces, walls and floor). If you didn't have any CYA in the water, then the reaction rate of FC will be higher and most likely your FC level will be lower since it's so strong without CYA moderating its strength. So it's much more likely to run out (go towards zero) locally in areas of poor circulation in that case though normally in pools with higher bather load (so that there's more stuff that uses up chlorine in the water). If instead you have CYA in the water and a high enough FC to kill algae, then it is less likely to run out of chlorine locally. Think of the CYA as an active chlorine buffer holding it in reserve for when it is needed.

Now in spite of all that, the fact is that if circulation is really poor in an area, then algae can still grow because if your FC/CYA ratio is close to the algae inhibition limit in most areas of the pool but the FC drops in areas of poor circulation, then algae could grow faster than chlorine can kill it. So while the CYA buffering of chlorine helps prevent chlorine from completely running out, it doesn't necessarily help it from preventing algae completely in areas of very poor circulation. The chlorine/CYA chart guidelines are just that, guidelines. They aren't absolutes and one can readily create situations where those recommended levels won't be good enough, but for MOST pools the recommendations work very well.

[PBLsQuad450]

Thank you Both! chem geek, that is a great explanation. The sanitizing action is almost counterintuitive for me so pardon the repeat question. I am glad I have a normal pool. I also vac by hand and take a few extra minutes each time to do stair fronts, side walls and and the like. Those areas get done maybe a little less than 2X per month where the pool is vacuumed every week, at least. This is an important caveat in understanding sanitizing. Thanks again!

Paul