Chlorine Loss

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BRM24

Chlorine Loss

Postby BRM24 » Mon 25 Jun, 2012 16:49

I have a 12' x 36" pool. I have been unable to maintain chlorine in the water. I use regular 6% bleach for chlorine source and just started experimenting (unsuccessfully) with 1" chlorine tablets in the filter cartridge because it said it had stabilizer in it to protect against sun consuming it. Also tried stabilizer granules which did nothing. I have to add chlorine everyday. How can I fix this problem??!!


chem geek
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Chlorine Loss

Postby chem geek » Mon 25 Jun, 2012 20:42

It sounds like your Cyanuric Acid (CYA) level might be too low so that the chlorine is getting broken down by the UV in sunlight. However, to know this for sure, you need a proper test kit. Please read the Pool School to learn how to maintain your pool and get one of the test kits in the "Test Kits Compared" section.
PoolDad
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My Pool: 15x36 Intex

Chlorine Loss

Postby PoolDad » Fri 29 Jun, 2012 22:14

OK, I'm in a similar situation to BM24, only my pool is 15' x 36", one of those 'easy set' things, paid a total of $150 for the pool and have put another $150 into other things trying to get it going and stable. :crazy:

I started out filling it with my well water, which is pretty hard ( lots of iron and lime ). It looked kinda green from the moment I filled it up, my immediate conclusion was that it was green from being yellow hard water with a bluish bottom of the pool making the water look green. My wife however was convinced I had algae, however I was highly skeptical of that since the water was still about 55F and had been in the pool less then 12 hours.

Long story shorter after a week of putting mostly sodium hypochlorite in it, keeping it above 1PPM chlorine the whole week, at times up near 5PPM chlorine (Total Chlorine)... and cleaning the cartridge filter at least every two days, the water is mostly clear and no longer green.

After the first day or two of seeing the chlorine dissipate nearly completely each day, pouring more in each night, I decided to try putting some of the 1" tablets in the pump rather then having to keep pouring chlorine in repeatedly. At first the three 1" tablets alone didn't seem to keep the chlorine level high enough so I added another three. At that point the chlorine level stayed up above 3PPM, maybe even going higher, I found/find it hard to read the OTO test thing, test strips said it was around 3PPM, but at times the OTO looked like it was at 5PPM. I started thinking I had put too many tablets in and had the chlorine level too high, so I started doing more research... Found this forum , which was indeed a good thing.

Oh, another thing... my PH was around 7.2, or 7.4, but my Total Alkalinity was like 300PPM, so I found the add muriatic acid and aerate method of bringing down TA, got that down to about 180 now, may try to get it a little lower eventually, but for now 180PPM TA doesn't alarm me.

OK, so... that I learned a little about CYA and Trichloro-s-triazinetrione having CYA in it, I'm trying to stop using the Trichloro-s-triazinetrione, or maybe just sort of wean myself off it, and watch my CYA get to a reasonable level and then stop using the Trichlor... But my 6-way HTH test kit can only do like two CYA tests before it's used up , I already did one, which told me I have virtually no CYA at this point ( I've only used like seven 1" Trichloro-s-triazinetrione Tablets to this point ).

I purchased a chlorine stabilizer & conditioner which lists the ingredients as 2,4,6 Trihydroxy-s-triazine 100%. On the back of this container, it says that this stuff IS Cyanuric Acid, doing some googling seems to confirm that 2,4,6 Trihydroxy-s-triazine, is indeed CYA. However, I've searched this site and others related to pools, and no one seems to mention 2,4,6 Trihydroxy-s-triazine. What is usually mentioned is Dichlor, etc...

I think, that this stabilizer is indeed 100% Cyanuric Acid ( 100% CYA, no chlorine in it ), I wonder if someone here can confirm this for me.

Another question I have... If I do get say 30PPM of CYA in my water, can someone give me some sense of how often I may need to add sodium hypochlorite? can you go a few days without adding more? or what?

OH, I did order a Taylor K-1515A Chlorine FAS-DPD Drop Test Kit, so I will soon be able to accurately measure my TC and FC, I didn't want to spend more then the $32 I spent on this test kit, since I already have put more into chemicals and such then I have into the pool itself. I have one more shot at a CYA test from my HTH 6 way kit.
chem geek
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Chlorine Loss

Postby chem geek » Sat 30 Jun, 2012 00:07

Look at TFTestkits where this CYA test gives you 16 tests for $17. 30 ppm CYA probably won't be enough to keep your chlorine loss low from sunlight. You might need something closer to 50 ppm, maybe more if you get a lot of sun. Typical daily Free Chlorine (FC) use is around 2-3 ppm. Again, read the Pool School for more info including the appropriate FC level for your CYA level to prevent algae growth.

2,4,6 Trihydroxy-s-triazine is a chemical synonym for Cyanuric Acid.
PoolDad
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Posts: 3
Joined: Fri 29 Jun, 2012 21:11
My Pool: 15x36 Intex

Chlorine Loss

Postby PoolDad » Sat 30 Jun, 2012 08:58

Looking closer at the amount of reagent needed for CYA test that came with the 6-way HTH test kit, it seems maybe I can get another 2 tests out of it.

I also found 2 ounces of Taylor reagent that I can get for $5 ( including shipping), I can just reuse my HTH tube and measure/sample bottle. I should be able to get maybe 6 or 7 CYA tests with this amount of reagent, which should easily get me though the rest of the summer ( two months maybe tops up here in Michigan).

I'll keep reading the pool school articles and see if i can get a better handle on all this, while I wait for my testing supplies to arrive.

Good to know that my 2,4,6 Trihydroxy-s-triazine, really is CYA... I added 8 ounces over the past 12 hours, which in theory should get me up to about 23 PPM of CYA, in my 2400 gallon pool. (if my math is close). If I added another 8 ounces I'd be up close to the 50 PPM mentioned by Chem Geek.

We will likely get a good bit of sun here in Michigan though July and August, after that... well it's anyone's guess. I'll probably tear down the pool in early September. If I'm lucky (assuming it managed to store it for the winter without getting holes in it) I will put it back up next June. Hard to justify too much more in the way of testing supplies for such a short season. I do know I have learned a lot in the first week of owning this thing, yet still have more to learn obviously.

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