green pool water with hgih chlorine levels

Algae problems in swimming pool water.
Green (cloudy) water or slimy pool walls.
Black algae. Mustard algae. Pink or white pool mold.
Candice G

green pool water with hgih chlorine levels

Postby Candice G » Wed 18 Jul, 2007 08:53

This year our pool has never been completly clear. It has been so close but never quite clear enough. Because of this we have kept our chlorine levels high (10).

Last week the tree farm behind us sprayed something on the trees. 3 days later our pool was green. Every day that our solar blanket was on it seemed to get worse. We have the solar blanket off now but it is still green.

We have shocked and added algaecide but I find it hard to believe that we could have algae with such high chlorine levels.

Our pool levels are good
CYA 100
TOT & FREE CHLO 10
PH 7.5
TOTAL ALK 120
HARDNESS 500

If anyone has a suggestion it would be VERY much appreciated! Before we go crazy!!!! :x


Backglass
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Re: green pool water with hgih chlorine levels

Postby Backglass » Wed 18 Jul, 2007 09:19

Candice G wrote:This year our pool has never been completly clear. It has been so close but never quite clear enough. Because of this we have kept our chlorine levels high (10).

Last week the tree farm behind us sprayed something on the trees. 3 days later our pool was green. Every day that our solar blanket was on it seemed to get worse. We have the solar blanket off now but it is still green.

We have shocked and added algaecide but I find it hard to believe that we could have algae with such high chlorine levels.

Our pool levels are good
CYA 100
TOT & FREE CHLO 10
PH 7.5
TOTAL ALK 120
HARDNESS 500

If anyone has a suggestion it would be VERY much appreciated! Before we go crazy!!!! :x


It's not the farmer neighbor...it's your CYA. Yours is double the maximum recommended value of 50ppm. (30ppm is optimal). CYA (Stabilizer) shields chlorine from the sun and makes it last longer but at high levels it also inhibits chlorine from working at all, requiring higher and higher doses to do the same thing.

Even with a chlorine level of 10, you can have algae with high CYA. Unfortunately the only reliable way to reduce CYA is via dilution. You must drain a foot or two of your pool and refill with fresh water...then retest until it comes down.

You should start using straight chlorine (bleach) asap instead of stabilized chlorine (pucks, etc) as this will only adding to your CYA problem.
===============================
I'm no expert...just a long time pool owner. The real experts are at www . troublefreepool . com

Download Bleachcalc free at troublefreepool . com /files/BleachCalc262.exe and start saving money on chemicals.
chem geek
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Postby chem geek » Wed 18 Jul, 2007 10:31

I think the slight cloudiness is also due to the combination of pH, TA and CH since both TA and CH are high. I calculate a saturation index of +0.2 which isn't that high, but if the pH goes up at all then the water can get more cloudy, especially if Cal-Hypo is used as a chlorine source or for shocking (which I'm guessing it is since it add calcium and the CH is high -- unless the fill water was initially very high in CH). Are you also using Trichlor tablets? That would explain the high CYA levels -- I'm guessing you are using Trichlor for chlorine most of the time and using Cal-Hypo for shock, is that right?

I agree that the high CYA is harder to deal with since you need to keep the Free Chlorine level higher, but having it at 10 ppm (target 11.5, but absolute minimum of 7.5) should keep away algae unless you've already got a bloom developed that is consuming chlorine quickly.

As for the spray on the trees, if that was some sort of fertilizer or other chemical containing phosphates and maybe nitrates, then that is essentially algae food so could certainly accelerate algae growth. Though you could try and battle this with more shocking and higher FC maintenance, I agree with Backglass that a partial drain/refill to get your CYA level lower will make pool management easier since it will take less FC to do anything -- to shock or to maintain chlorine levels. This is because you most efficiently shock with a constant FC level of 40% of the CYA level. You then after all algae is gone, the FC holds overnight, and you measure no CC, you target an FC of 11.5% of the CYA level (with an absolute minimum of 7.5% of the CYA level).

After you've lowered your CYA via a partial drain/refill (about half of the pool water), your TA will probably be lower as well which is good and what you want since that will also help reduce cloudiness.

If you don't have one already, get yourself a good test kit, the Taylor K-2006 or the even better TF-100 from tftestkits(dot)com.

Richard
Candice G

Postby Candice G » Wed 18 Jul, 2007 13:42

Thank you for both responses!

How much bleach should I add? We have a 16 x 32 inground 3ft to 8ft pool.

Thanks again!
chem geek
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Location: San Rafael, California

Postby chem geek » Wed 18 Jul, 2007 14:15

16 x 32 x ((3 + 8 ) / 2) = 2816 cubic feet = 21,065 gallons so let's just call it 21,000 gallons.

One gallon of 6% unscented bleach (Clorox Regular or off-brand Ultra) will raise the Free Chlorine (FC) by 2.9 ppm, but note that most jugs are 96 ounces so that will raise the FC by 2.2 ppm in your 21,000 gallon pool.
Guest

Postby Guest » Fri 20 Jul, 2007 08:57

So I drained about half of the pool, and refilled it. My CYA is now at 50.

I have added the past two days 5 gallons of unscented bleach. It is still green. Not as green but definitly green and you can barely see the shallow end.

We have a pool party scheduled for Monday and I am starting to think there is NO way it is going to be ready.

Someone told me to super floc it. Is this a good idea? It seems like it takes a long time to do and since I work all weekend I don't know if I will have time.

Any other suggestions?
Backglass
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Postby Backglass » Fri 20 Jul, 2007 10:26

Anonymous wrote:So I drained about half of the pool, and refilled it. My CYA is now at 50.

I have added the past two days 5 gallons of unscented bleach. It is still green. Not as green but definitly green and you can barely see the shallow end.

We have a pool party scheduled for Monday and I am starting to think there is NO way it is going to be ready.

Someone told me to super floc it. Is this a good idea? It seems like it takes a long time to do and since I work all weekend I don't know if I will have time.

Any other suggestions?


What are your chlorine readings? You may have already used up the 5 gallons you added. You must get your pool to shock levels and maintain it for at least 24 hours. Sometimes this means adding chlorine every day or multiple times a day until it stabilizes. If you ket the chlorine drop to -0-, you are starting from scratch every time. Be sure to run your filter/pump 24/7.
===============================

I'm no expert...just a long time pool owner. The real experts are at www . troublefreepool . com



Download Bleachcalc free at troublefreepool . com /files/BleachCalc262.exe and start saving money on chemicals.
Candice G

Postby Candice G » Sat 21 Jul, 2007 10:22

After I refilled the pool my chlorine level was still reading past ten (I have the test strips) the only level that changed any was my CYA so now the chlorine level is REALLY high! Sorry I guess I should've posted that last time!
Candice G

Postby Candice G » Sun 22 Jul, 2007 17:37

I was reading on the web and am positive the type of algae I have is Mustard Algae.

The website I was on said that this type of algae can live in high levels of chlorine. Should I just shcok & floc or should I buy some of the expensive yellow out algaecide?

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