Potassium Monoperslfate Overdose

[wsommariva]

Last October I closed the pool and added either 5 or 10 times the amount of pot monopersulfate that I should have. Was told not to worry it would dissapate.

So I open the pool and it has a nice light green color to it. I think it's the overdose effect. Temp of the water is 54, so I doubt it's algae.

Any thoughts ?

Thank you

[chem geek]

Unless the overdose caused oxidation of copper, such as in a heat exchanger, the green is probably algae. Algae can grow, albeit more slowly, in a colder pool. Some have even seen it grow under ice.

You can have the water tested for copper. Or you can just lower the pH and see if it lightens up -- if it does, it's likely to be copper. If it's a cloudy green rather than a clear green, it's more likely to be algae and chlorine will kill it.

[wsommariva]

Ok, here's the entire situation, maybe you can help.

I use a CL free system. I have copper and titanium plates within the PVC pipes connected to low voltage electricity. The copper is maintained at .7 ppm. When I opened the pool it was at .5

The green color is light green. I hope it's the pot mono per sul and it will disipate when the water gets warmer, it's now at 52 degrees.

Also, I added 14 ounces of Algae 60 a week ago; this did not affect the green color.

Any thoughts?

Thanks

[chem geek]

Thanks for the additional info. I didn't know you were using CL Free. Yes, that has copper in the water and the clear green color is most likely due to that copper level. If you are going to have a high level of copper -- and 0.7 ppm is high -- then the pH must be kept fairly low. I would check your pH and if it's higher than 7.5, then lower it, but not below 7.0.

[wsommariva]

PH is 7.5

I will lower to 7.0

I'll also lower copper to .6

Thank you very much

[chem geek]

Is your pool a plaster pool or have any exposed grout in tile touching the water? If so, then you need to be careful about lowering the pH too much without compensating with a higher Calcium Hardness (CH). If you have a vinyl-lined pool, then this isn't important. You can try lowering the pH to 7.2 to start with -- if that clears up the water then there's no need to go lower.

I assume you know that you can maintain your pool more easily with chlorine, but I figure you are dead-set on a chlorine-free system. The problems you are having are typical of those who have metal ion systems. Unfortunately, the level of metal ions needed to prevent algae growth are close to the levels where they cause blond hair to get a greenish cast, cause water to look greenish, and stain plaster surfaces unless the pH is kept low which has its own problems. It's a careful and delicate balance. Plus, it's not as sanitary as chlorine -- even with silver ion in the water, bacteria take at least 10 times longer to get killed and viruses are effectively not inactivated in any reasonable amount of time (I write more about this in this post).

[wsommariva]

I have a fiberglass pool. I'll set the PH at 7.2

I wanted chlorine, my wife wanted CL free. She wins all battles. But, the CL free system is working quite well.

Thanks again