chlorine turns pool green

What is floc, clarifier, stabilizer, cyanuric acid,
algaecide, brightener, dichlor, sodium hypo,
sodium bisulfate, ....??
0wner

chlorine turns pool green

Postby 0wner » Mon 25 Aug, 2008 10:28

when I shock my pool the water turns green for a day?


chem geek
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Postby chem geek » Mon 25 Aug, 2008 12:33

You probably have copper in the pool. Adding a hypochlorite source of chlorine makes the pH rise until the chlorine gets used up when it drops back down. Higher pH makes copper precipitate leading to green water color and possible staining (especially on plaster surfaces).

Have your water tested for copper just to be sure and if it's present, lower the pH and add a metal sequestrant and then slowly raise the pH back to normal.

Richard
owner

chlorine turns water green

Postby owner » Tue 26 Aug, 2008 12:05

thanks for the help, but is there any other reasons that when i shock my pool the water turns green
chem geek
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Postby chem geek » Tue 26 Aug, 2008 12:13

Not that I know of. Do you know that there is no copper in the pool? Some algaecides contain copper. Green is either copper or algae, but since it shows up for you when you shock the pool and I presume you are using a hypochlorite source of chlorine for shocking that raises the pH, then it's most likely to be copper, especially since it fades as the pH drops back down as the chlorine gets used up.
owner

green water

Postby owner » Tue 26 Aug, 2008 16:40

We had the water tested, it showed no copper. However, I'm not convinced the young man knew what he was doing, he seemed confused.
I'll get it re-tested and go from there. Other then copper algaecides or a heater could there be anything else putting copper in the water? If not, no reply is necessary. Thank's for your help!
chem geek
Pool Industry Leader
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Postby chem geek » Tue 26 Aug, 2008 19:57

Other than the two sources you mentioned, the only other one I can think of is a metal ion system such as Nature2 or the equivalent "liquid" metal ion products.

You could take a bucket of pool water and add some pH Up (sodium carbonate) to it which should not only turn it green, but should precipitate some of this stuff. It might also precipitate calcium carbonate depending on how much you add, but that would be white. If it's copper, then copper carbonate looks green like this while copper hydroxide looks green like [url=http://en.wikipedia.org/wiki/Image:Copper(II)_hydroxide.JPG]this. Either one will form at higher pH if there is copper in the water.

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