Adding BBB

I haven't found a sticky regarding how to add BBB and in what order.
It makes sense that bleach should be broadcasted but what about Borax and baking soda? Through skimmer or broadcasted. Also, suppose everything has to be adjusted
during spring opening, what is the order of chemical addition, including TA, CH and shock?

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Originally Posted by Water_man

I haven't found a sticky regarding how to add BBB and in what order.
It makes sense that bleach should be broadcasted but what about Borax and baking soda? Through skimmer or broadcasted.
Into the skimmer is fine. Make sure the pump is running.

Also, suppose everything has to be adjusted
during spring opening, what is the order of chemical addition, including TA, CH and shock?
It really depends on what the numbers are. but generally adjust TA and pH first and then adjust CH. Also, shock is a verb, not a noun. That means it's something you do to a pool, not a specific product. Any of the unstabilized chlorines are suitable for shocking--sodium hypochlorite (bleach), calcium hypochlorite (what is commonly sold as 'shock' in 1 lb bags--will cause calcium hardness to rise), lithium hypochlorite (THE most expensive form of chlorine you can buy). I would not recommend using dichlor for shocking on a regular basis (also sold as shock sometimes) because it will cause your CYA levels to rise very quickly and can lead to an overstabilized pool with it's associated problems of algae outbreaks, cloudy water, and, in worst case, black spot algae or white water mold and pink slime (pink algae).

If you could post a full set of test results for FC, CC, TC, pH, TA, CH, and CYA it would give us information so we can give you better advice as to which needs to be adjusted first. Sometimes the very first adjustment is to either add CYA if it is below 30 ppm or to start a cycle of partial drain and refills if the CYA is too high and the pool is overstabilzied (usually over 50 ppm is too high for a manually chlorinated pool but slightly higher levels are managable if adjustments to your FC and shock levels of chlorine are made.)

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Hope this is helpful.

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Originally Posted by waterbear

Hope this is helpful.

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Thank you, Waterbear. Until being "re-educated" by this forum I used stabilized trichlor tablets for maintaining 3 ppm chlorine and calcium hypo to shock (2 to 3 lbs.) I intend to use my remaining stock of tablets until they run out, and to shock with bleach. Soon the pool will be reopened and I'll have all the numbers. BTW, I assume that most pool owners, including bewbees, understand that "shock" is a verb. I assume you and others who remind this to us mean that just adding FC won't shock, if not done right and with the proper amount. "Ben's Best Guess CYA chart" determines the amount of free chlorine neeeded to shock a pool as a function of the CYA level. I found other publications that determine the amount of needed FC by simply multiplying the CC by 10, regardless of the level of CYA.
Here's one of these links, provided by Indiana State Health Dept http://www.in.gov/isdh/regsvcs/sanen...pool_shock.htm

Why do they ignore the CYA level and why Ben's chart doesn't use the 10 X CC rule to calculate the FC needed to shock? I'm sure that CYA and CC levels are totally independent and it seems that both chemical species should be considered when it comes to calculate the FC needed to shock.

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Originally Posted by Water_man

Why do they ignore the CYA level and why Ben's chart doesn't use the 10 X CC rule to calculate the FC needed to shock? I'm sure that CYA and CC levels are totally independent and it seems that both chemical species should be considered when it comes to calculate the FC needed to shock.

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There are many possible answers as to "why" but that really doesn't matter. The chlorine/CYA relationship in terms of the equilibrium chemistry, and specifically the fact that the FC/CYA ratio roughly determines the amount of disinfecting chlorine (hypochlorous acid), was definitively determined in a scientific paper written and presented at a symposium in 1973 and published in 1974. That's nearly 35 years ago. By comparison, the dangers of smoking were first known in the 1950's and only more fully acknowledged by that industry in the 1990's, a period of roughly 40 years. Perhaps there's pride in trying to break a world record here. :rolleyes:

But even ignoring that chlorine/CYA relationship, one can also ask why the following basic rules are not taught by APSP Tech or NSPF CPO:

For every 10 ppm Free Chlorine (FC) added by Trichlor, it also increases Cyanuric Acid (CYA) by 6 ppm.
For every 10 ppm FC added by Dichlor, it also increases CYA by 9 ppm.
For every 10 ppm FC added by Cal-Hypo, it also increases CH by 7 ppm.

Those are chemical facts independent of concentration so should be easy "rules-of-thumb" taught in courses, wouldn't you think? A little simple math assuming just 1 ppm FC per day using Trichlor tabs/pucks means that CYA would climb by over 100 ppm in 6 months, ignoring dilution (from splash-out, backwashing, etc.).

As for shocking, Ben's chart is referring to a shock level used to clear algae at a reasonable rate. Though it can also be used to more rapidly clear Combined Chlorine (CC), most outdoor pools exposed to sunlight and properly maintained with sufficient FC relative to CYA simply don't get much measurable CC. Technically speaking, even the 10x rule for CC is inaccurate. The chemistry behind the 10x is for the amount of chlorine (in ppm FC which is a "chlorine gas" equivalent) needed to oxidize an amount of ammonia (in ppm Nitrogen) and comes from an actual stoichiometric (ppm-based) amount of 7.6 that becomes more optimal in the range of 8-10. However, for CC (which is measured as chlorine, not ammonia-nitrogen), you technically only need half of the CC amount in FC to "break" it (assuming the CC is monochloramine). The extra chlorine for shocking to get rid of CC just makes it go faster, but in a properly managed pool the disinfecting chlorine is continually breaking down ammonia/urea from bather sweat and you do not need to shock.

There are many myths in the industry and I'm slowly putting together something of a training program that I hope will correct or augment current training (see this post), but this will take time and the industry has so far not been receptive to change. I don't give up, however, because there's something about truth that drives persistence.

Richard

Chemgeek basically said it all. I really have nothing to add.

If I maintain my FC according to the "Ben's Best Guess CYA chart" (my current CYA reading at opening is 56) and suppose I don't have algae, do I still need to shock on a weekly basis? Is the need to shock determined by the level of CC? If yes, what's the upper limit of CC ?

If you don't have algae (or unusually high chlorine demand or water turning dull or cloudy) and you have <= 0.5 ppm CC, then you don't need to shock. Even if you have some CC that's a little above 0.5 ppm, you could wait a while and see if a sunny day plus some time takes care of it. Usually this would happen after a heavier bather load -- you could shock if you wanted to, but could just wait a day or two instead.

Sometimes if I get a suntan lotion film on the water and am impatient at getting rid of it, I'll shock or use a non-chlorine shock. I use the the latter if my wife is swimming every day and doesn't want to be in at higher chlorine levels. This situation is rare -- I've only done it once and usually I just let the film be as it does clear up if she doesn't keep adding to it every day.

Richard

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Originally Posted by Water_man

(my current CYA reading at opening is 56) and suppose I don't have algae, do I still need to shock on a weekly basis? Is the need to shock determined by the level of CC? If yes, what's the upper limit of CC ?

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How are you testing? Most CYA tests do not have the resolution to give a reading like 56 ppm. Even the $1000 colorimeter/turbidity meter we use at work is +10/-25 ppm for the CYA test.

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Originally Posted by waterbear

How are you testing? Most CYA tests do not have the resolution to give a reading like 56 ppm. Even the $1000 colorimeter/turbidity meter we use at work is +10/-25 ppm for the CYA test.

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The colorimeter at the pool supplies store.
My Taylor kit is due any day now. Does it have a better res?

Are thet usuing a colorimeter with either liquid reagents or dry reagents in a vial or are they using a strip reader with test strips?

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Originally Posted by waterbear

Are thet usuing a colorimeter with either liquid reagents or dry reagents in a vial or are they using a strip reader with test strips?

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The store tech pipetted the water samples into sealed rectangular shaped vials that must have contained reagents (I'm not sure if they were liquid or dry) and then she took the reading off the colorimeter.

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Originally Posted by chem geek

If you don't have algae (or unusually high chlorine demand or water turning dull or cloudy) and you have <= 0.5 ppm CC, then you don't need to shock. Even if you have some CC that's a little above 0.5 ppm, you could wait a while and see if a sunny day plus some time takes care of it. Usually this would happen after a heavier bather load -- you could shock if you wanted to, but could just wait a day or two instead.

Sometimes if I get a suntan lotion film on the water and am impatient at getting rid of it, I'll shock or use a non-chlorine shock. I use the the latter if my wife is swimming every day and doesn't want to be in at higher chlorine levels. This situation is rare -- I've only done it once and usually I just let the film be as it does clear up if she doesn't keep adding to it every day.

Richard

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Thank you, Richard. Unfortunately, I haven't found yet on the board a sticky that deals with these questions.
Here's are some further questions:
1. Suppose the CC is > 0.5 and there's no algae condition. Do I still need to use the "Ben's Table" , or should I use the 10x CC rule? I'm asking because with my CYA level of 56 , the 20 ppm FC level off the Table seems high. How long would it take for the FC to dissipiate and thus enabling a safe for swimming level of FC?

2. If CYA is stable, as I've read here, and since it protects FC from UV, then how come it is still mentioned here in many places that one should shock in the evening, otherwise the FC will be quickly destroyed by the Sun's UV?

3. I'm sure that no such thing as "average bather load" is accurately defined, and that other bio-enviromental factors are involved, but, what frequency can I expect of FC addition in order to mainatin my normal FC level? Is it daily, or twice a week, or what?

4. What's the best thing to do when one goes on a 1- 2 week vacation and the pool is left unattended?
Shock before you leave? Add trichlor tablets?

Please let me know if a FAQ answering all these questions and other, related ones is posted here or elsewhere. If not, I'm sure it would be very helpful and would save a lot of time and bandwidth.

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Originally Posted by Water_man

The store tech pipetted the water samples into sealed rectangular shaped vials that must have contained reagents (I'm not sure if they were liquid or dry) and then she took the reading off the colorimeter.

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Ok, That would be a LaMotte Waterlink or Waterlink Express. It's a pretty good system. We use the same at work. I will warn you that the TA test often reads low and so does the calcium hardness. It has to do with the limitations of the meter so if your Taylor test reads higher on these believe it.

My Taylor kit is supposed to arrive any day now.
Is the test's chem based on titration? Does it offer an accurate reading?

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Originally Posted by Water_man

My Taylor kit is supposed to arrive any day now.
Is the test's chem based on titration? Does it offer an accurate reading?

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which Taylor kit did you get? Hiopefully you got a K-2006 and not a K-2005.

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Originally Posted by waterbear

which Taylor kit did you get? Hiopefully you got a K-2006 and not a K-2005.

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K-2006. I'm a quick learner :)

My responses below in bold.

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Originally Posted by Water_man

1. Suppose the CC is > 0.5 and there's no algae condition. Do I still need to use the "Ben's Table" , or should I use the 10x CC rule? I'm asking because with my CYA level of 56 , the 20 ppm FC level off the Table seems high. How long would it take for the FC to dissipiate and thus enabling a safe for swimming level of FC?

If the CC is only a little high -- say 1 ppm or so -- then I'd just wait for the next day to see if sunlight helps get rid of it along with time from exposure to normal chlorine levels. If it's really high, then that's unusual and a shock level could be tried, but it could be persistent chlorine that virtually nothing but dilution will get rid of -- that's rare except in some indoor pools. I don't think the 10x rule is useful for CC, period.

2. If CYA is stable, as I've read here, and since it protects FC from UV, then how come it is still mentioned here in many places that one should shock in the evening, otherwise the FC will be quickly destroyed by the Sun's UV?

Quickly is a relative term. You are right that it isn't so quick and you can shock in the morning if you want to, but if sunlight cuts down chlorine over the day by, say, a third, then a third of a high FC shock-level number is quite a lot. If you shock at night, then you get the entire night at that high level compared to the daytime where only part of the day is at that high level and some of the day is at a lower level. It's not a huge deal -- just an optimization.

3. I'm sure that no such thing as "average bather load" is accurately defined, and that other bio-enviromental factors are involved, but, what frequency can I expect of FC addition in order to mainatin my normal FC level? Is it daily, or twice a week, or what?

That depends on the CYA level since sunlight is the biggest factor, generally more so than bather load unless you've got many people using the pool (not just 1-3). Dupont defines high bather load at < 1000 gal/bather/day, medium bather load at 1000-5000 gal/bather/day, and low bather load at >5000 gal/bather/day. This assumes some unknown amount of time, probably between 30 minutes and an hour of a bather in the water "per day". For manual dosing, one usually needs to add chlorine every day or two depending on CYA level and sunlight exposure. With a pool cover, one can usually add chlorine twice a week (that's my situation).

4. What's the best thing to do when one goes on a 1- 2 week vacation and the pool is left unattended?
Shock before you leave? Add trichlor tablets?

You can automate "liquid" chlorine dosing by using The Liquidator talked about in this thread which may last 2 weeks if there's no bather load. Otherwise, you either need to get someone to add the chlorine manually or you can use Trichlor tabs/pucks, but even with tabs/pucks the chlorine will likely only last about a week or week and a half -- probably not 2 weeks. Also, Trichlor is very acidic so you'll want to start out with the pH a bit higher. You can shock and after the chlorine drops some (over one day), then add a full dose of PolyQuat 60 algaecide similar to what is done on closing. Probably the best thing (other than having someone add chlorine) is having a pool cover that is opaque to sunlight as that can cut down the chlorine usage to 0.5 ppm per day or so.

Please let me know if a FAQ answering all these questions and other, related ones is posted here or elsewhere. If not, I'm sure it would be very helpful and would save a lot of time and bandwidth.

I don't think this info is in one place that I can find, but it is in various posts.

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Hope that helps.

Richard

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Originally Posted by chem geek

My responses below in bold.



Hope that helps.

Richard

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Thank you again, Richard, for this detailed response.
I understand that it's beyond the scope of this part of the forum, but I'd be interested to see the chemical details of the correlation between CYA level and the amount of FC needed to shock. You mentioned before a paper presented long time ago. Has anything been published so far on line?

Also, it's not easy to understand why such a high level of FC is needed to break 0.5 - 1 ppm CC in an alagae-free shock treatment. In my case it's 19.8 FC (CYA =50), taken from the table you posted at troublefreepools.com. Is it because of the fact that in the presence of CYA, "free" HOCl doesn't exist, but it's rather bound to CYA?
If we need to move on to the China Shop for this purpose, please let me know.

Continuing in the China Shop in this thread.

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Originally Posted by waterbear

Hope this is helpful.

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Got my Taylor k-2006 kit today! Impressive and worth the price! (got it from SPS -Swimming Pool Supply Company -good price and prompt shipping).
The pool (actually the "swamp") was opened last Friday.
Now it's sparkling blue, after performing the "usual" green pool routine (*) and lots of POPP.

Here are the numbers:

CYA 60
FC 7.5
CC < 0.5
TA 140
pH 7.9
CH 170

I followed your advice and started to take care of the pH and alkalinity. Since I have in stock "dry acid" I added half the calculated amount needed to bring it to pH 7.6.
I used 1 lb. One thing I learned here - slow down with adding chemicals!
I wonder where can I get muriatic acid. Home Depot doesn't carry it. Hydrochloric Acid (the actual compound) is cheap - I wonder if chemical supply houses sell it to residential end users.

(*) the "green pool routine" I used : shocked to 20 ppm first day and on day three, frequent backwashes, brushing, vacuuming, floc, robot cleaner.

It goes without saying that with 60 ppm CYA this pool won't see chlor tabs any more!

Any other suggestions?

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Originally Posted by Water_man

I wonder where can I get muriatic acid. Home Depot doesn't carry it. Hydrochloric Acid (the actual compound) is cheap - I wonder if chemical supply houses sell it to residential end users.

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Often it is in the paint department. Also, you can usually find it at ACE or other hardware stores (once again if they don't have a pool dept. check the paint dept.) or at just about any pool supply store.

Lowe's carries it, but it's more expensive than Home Depot around here. The cheapest place here is at the Tractor Supply Company (nationwide chain).

Janet