Dichlor, Polyquat 60, and borax questions

What is floc, clarifier, stabilizer, cyanuric acid,
algaecide, brightener, dichlor, sodium hypo,
sodium bisulfate, ....??
Ziora
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Dichlor, Polyquat 60, and borax questions

Postby Ziora » Tue 17 Jul, 2007 21:18

We have an inground pool with approx. 20,000 gal., vinyl liner, and sand filter. It is clear and looks great after a month-long fight with algae. I had to empty it halfway and refill twice to reduce the CYA. Today's levels are as follows:

TC: 2
FC: 2
pH: 7.4
TA: 120
CH: 20
CYA: 10
Phospates: Around 250

I put 4 oz. PolyQuat 60 in at 9:30 p.m. I've been using 6% Clorox to shock and maintain the chlorine levels. I used baking soda to raise the TA from near 0 to 120.

I have some Dichlor that I'd like to use up and it seems like it would be OK to add that to gradually raise the CYA to about 25. I'm adding Clorox more often than I think I will if I maintain a little higher CYA. Am I correct in assuming this?

How long should I wait after adding PolyQuat 60 to add the Dichlor and how long between each chemical should I wait before shocking with Clorox, if it should need that in the future? Will the 20 Mule Team Borax require any special waiting time if I need to raise pH after using the Dichlor?

I'm not sure how to guage the amount my CYA will increase by using Dichlor. Is it .9 for every 1ppm of chlorine added? I think this stuff also has an algaecide in it, but it doesn't say what kind. I don't know if it contains copper and if it will have a bad reaction with the PolyQuat 60 or not. Does anyone have an answer to this? I certaintly want to avoid any further water problems.

I've been waiting an hour before adding a new chemical and it seems like a general rule of thumb.

I really like being able to control the chemicals with more precision instead of just adding 3-in-1 or 6-in-1 stuff. The packages never seem to say exactly what all the chemicals are.

Important to note (and should have been common sense): I will wear rubber gloves from now on when using the PolyQuat. Just a little dot on my fingertip burned like heck for awhile.


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Re: Dichlor, Polyquat 60, and borax questions

Postby chem geek » Tue 17 Jul, 2007 21:52

With your 120 ppm TA level, you might find that your pool's pH tends to rise if you end up using bleach or chlorinating liquid as your primary source of chlorine. If that is the case, a lower TA will actually help (yes, this is counterintuitive -- TA both buffers pH AND is a source of rising pH due to carbon dioxide outgassing).
Ziora wrote:I have some Dichlor that I'd like to use up and it seems like it would be OK to add that to gradually raise the CYA to about 25. I'm adding Clorox more often than I think I will if I maintain a little higher CYA. Am I correct in assuming this?

Yes, more CYA should protect the chlorine better even though you have to maintain a higher FC level at that higher CYA level. This is relatively new advice since we used to think that there were diminishing returns to CYA because that's what some industry graphs showed, but recent experiments and experiences from some pool users has shown that even keeping the FC at the recommended 11.5% of CYA level (absolute minimum of 7.5% of the CYA level), the higher CYA and FC ends up losing less chlorine to sunlight.
Ziora wrote:How long should I wait after adding PolyQuat 60 to add the Dichlor and how long between each chemical should I wait before shocking with Clorox, if it should need that in the future? Will the 20 Mule Team Borax require any special waiting time if I need to raise pH after using the Dichlor?

You don't need to wait long at all -- even 10 minutes for some mixing should be OK so long as you have decent circulation. PolyQuat 60 needs to be distributed evenly around the pool as it is viscous so doesn't mix quickly so you should have the pump running for hours to mix it -- so it's probably best to add in the morning and get a full day of circulation. But you don't need to wait to add other chemicals. The only minor incompatibility is that shocking which chlorine will break down PolyQuat into smaller pieces, though they are still effective as an algaecide. However, this process uses up chlorine so trying to shock after adding PolyQuat ends up wasting some chlorine and adding lots of PolyQuat may use up some chlorine -- just be aware of that.

No need to wait between the Borax and Dichlor. Dichlor will be somewhat acidic -- initial addition isn't very acidic, but the usage of chlorine will be acidic so keep that in mind. You should generally just adjust pH when chlorine levels are at normal levels -- especially because high chlorine levels bleach out parts of the pH indicator (above 10 ppm FC).
Ziora wrote:I'm not sure how to guage the amount my CYA will increase by using Dichlor. Is it .9 for every 1ppm of chlorine added? I think this stuff also has an algaecide in it, but it doesn't say what kind. I don't know if it contains copper and if it will have a bad reaction with the PolyQuat 60 or not. Does anyone have an answer to this? I certaintly want to avoid any further water problems.

Yes, for every 1 ppm FC added by Dichlor you will add 0.9 ppm CYA. I doubt that the Dichlor has an algaecide in it, but if you post the brand name I can try and look up the MSDS online (or you can try that and see what it says). It is true that some chlorine has copper as an algaecide in it so you are right that you need to be careful.
Ziora wrote:I've been waiting an hour before adding a new chemical and it seems like a general rule of thumb.

I really like being able to control the chemicals with more precision instead of just adding 3-in-1 or 6-in-1 stuff. The packages never seem to say exactly what all the chemicals are.

Important to note (and should have been common sense): I will wear rubber gloves from now on when using the PolyQuat. Just a little dot on my fingertip burned like heck for awhile.

The hour rule is fine though isn't always necessary if you have good circulation. Only the PolyQuat takes over an hour to mix. Everything else should be fairly well mixed in 15-20 minutes with decent circulation (though as I said above, even 10 minutes is pretty good). I've done "Party Blue" dye tests on my pool by pouring over a return with the pump running (my pool has a floor drain so has very good circulation) so you can always get some of that to test your circulation if you are concerned. The main problem with above-ground pools is that most do not have a floor drain and that causes poor circulation near the bottom of the pool.

I've never noticed the stinging with PolyQuat, but it works by blocking ion channels so perhaps by doing so with skin nerve sensors this produces a stinging effect. It's not toxic to you via touch -- skin is rather resilient -- but you might as well use gloves to not feel uncomfortable. The only really nasty chemical is Muriatic Acid (which is also an irritant in the nose with its fumes). The others aren't great, but don't generally have as much direct effect on skin -- not even Trichlor tabs. But using gloves is safer in any event.

Richard
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Lots of info to digest

Postby Ziora » Wed 18 Jul, 2007 22:57

Thanks a bunch for answering my questions. I feel much more confident about adding the chemicals.

As for the PolyQuat reaction...I wouldn't describe it as a stinging. It felt like a burn. It is still sensitive today. Just one of those things, I guess.

I'm trying to get a better understanding of CYA levels and found the following site. I hope the information is not so outdated that I wasted my time.

www dot ppoa dot org/pdfs/PrP_Cyanurics%20-%20Benefactor%20or%20Bomb.pdf

What I gathered (in very simple terms), keeping my CYA at 10ppm would seem to be more beneficial at killing the algae and bacteria faster, but inconvenient because it requires more frequent dosing of chlorine. Keeping it at 20ppm means I have less chance of the chlorine dropping too low and risking an algae bloom because it binds with the chlorine to keep it around longer. It also means it takes longer to kill the bad stuff and I have to use more chlorine to keep the FC at a higher level. It doesn't seem like it's a matter of economics as much as convenience. I don't have to worry about diseases as much as algae since it's a private pool, so it's more curiosity than anything. Still, I think it's important to understand as much as I can about it.

I've got a clear pool after 1 nasty storm and 2 days of rain. I haven't shocked it since getting rid of the algae. That's pretty cool and definitely a first for not having algae after a rain.

The following is what I understood from the link:

Diichlor does not actually contain an algaecide. It is promoted as an algaecide because it will help kill algae. It is, by weight, 57% cyanuric acid. I don't think I have to be concerned with copper.

Trichlor has a characteristic pH of 2.9. Trichlor is, by weight, over 54% cyanuric acid. I won't be putting those sticks in my skimmer basket.

CYA, at levels over 70 reduce chlorine's ability to properly sanitize. No amount of residual will kill harmful bacteria fast enough. At levels over 100, health becomes an issue because of the increased time the chlorine takes to kill the bad stuff.

There was also some very interesting information on TDS. I didn't realize TDS was mostly salt.

I was at the grocery store today and saw some clorox toilet bowl cleaner in slow disolving pucks. It got me wondering what is in 2000 flushes. Wouldn't it be convenient if that stuff worked for pool water on those days you have to be out of town.
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Postby chem geek » Thu 19 Jul, 2007 00:39

Though the link does have a lot of useful information, it is not all correct as we are finding out. It is not true that at higher CYA levels that no amount of chlorine will be effective. The relationship between chlorine and CYA is well understood as a chemical equilibrium between a variety of compounds. The basic research for this described technically in this thread that I wrote and is based on chemical equilibrium constants determined back in 1973 so it's not as if this is new. It's just been obscured by chemical manufacturers who claim that CYA is no problem and that only Free Chlorine levels matter.

Anyway, the bottom line is that for CYA being much higher than the FC level, which it is in pools, the disinfecting chlorine level is determined from the ratio of FC to CYA. So doubling your FC when the CYA doubles keeps the disinfecting chlorine level constant which keeps the rate of killing algae, bacteria, viruses, oxidizing organics, etc. all constant. So you can absolutely have higher CYA, but you need a correspondingly higher FC level. For manually dosed chlorine pools, a good target FC to keep away algae is 11.5% of the CYA level with an absolute minimum FC of 7.5% of the CYA level.

The graph showing diminishing returns for CYA protection of chlorine degradation from the UV rays from sunlight appears to be incorrect since it does not account for the protection that comes directly from CYA absorption/extinction of UV rays (the graph only shoes the protection from having most of the chlorine bound to CYA and degrading more slowly). We are currently sorting this out through experiments and data from pool users and I'll post new graphs at some point.

I don't know what is in the clorox toilet bowl cleaner but would suspect it has items that you do not want to put in your pool. If you get an ingredients list and can post it, that would be great. [EDIT] I just found the MSDS for this product here and it indicates that the product contains the equivalent of what is in bromine/chlorine combo tablets as well as boric acid. This is NOT something you want to add to the pool since the bromine delivery component (dimethylhydantoin) does not break down readily and the bromine turns your pool into a bromine pool and is less effective as a disinfectant and consumes the chlorine to reactive it and is not protected from destruction by sunlight (so essentially, it accelerates the using up of chlorine quite rapidly as the chlorine is constantly trying to convert bromide back to bromine which the sun breaks down.

That's all for now.

Richard
Ziora
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Postby Ziora » Thu 19 Jul, 2007 13:16

Thanks for posting the link for the clorox cleaner. I couldn't find the MSDS for 2000 flushes bleach from the mfg., but found it on another site. I think it's the same as Cal-Hypo. I was just curious about it. I'd get it at the pool store before using it since I'd have no idea how much to use. Interesting though, that it's the same stuff. 2000 Flushes

This is another one from the mfg that lists the ingredient in another product as organic chlorine bleach, whatever that is. 2000 Flushes
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Postby chem geek » Thu 19 Jul, 2007 20:49

I looked at those links and this link is to all the 2000 Flushes products by WD-40 and they all just say "organic chlorine" which could just be Trichlor and I suspect it is since that's the most common form of organic chlorine that can be put into tablets or pucks.

Cal-Hypo can be made into tabs/pucks, but wouldn't be called "organic chlorine" so I don't think that's it. Anyway, I would still be wary of using 2000 Flushes since it may not be pure Trichlor and if it is Trichlor it adds to CYA. Generally speaking, Trichlor is the least expensive source of chlorine -- it just unfortunately adds to CYA which is fine when you need it but not when you don't (boy, that sounded obvious, didn't it).

Richard

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