Green water from metal?

I have a 30 foot round AG pool. We did not cover it this winter and it got filled with algae, but we were able to treat that and get rid of it. However, once the water was blue, every time we put liquid chlorine in to shock, it would turn clear green. I had the water tested 3 times at different places and everything came back fine. I tested for iron and copper, but found none. Everyone kept telling me it was caused by algae bloom when the chlorine was added. I did not see how this is possible after we had shocked so many times, so I added a metal chelator and that took care of the problem.
I am still baffled at what kind of metal it could have been in the pool, and how did it get there. I have never had a problem like this before. Any ideas??:confused:

if it was a bright green it was most likely copper. Just because a pool store said there was no copper in the water doesn't mean there wasn't. We all know that their testing can be suspect! the fact that a seqestering agent took care of the problem (sort of--the metal is still in your pool and can return) indicates that the problem was probaby metal induced. What type of treatment did you use for the Algae? Many algecides are copper based!

What do you mean about it still being in the pool and can return? I thought that once I put that stuff in there, that the filter picked it up or something. Does that mean I have to keep treating it? How do I get it out all together? I do not want GREEN Hair!! How did it get there in the first place? I did not think this was a common problem with an above ground pool.

I only used chlorine to treat the algae.

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Originally Posted by Lschaal

What do you mean about it still being in the pool and can return? I thought that once I put that stuff in there, that the filter picked it up or something. Does that mean I have to keep treating it? How do I get it out all together? I do not want GREEN Hair!! How did it get there in the first place? I did not think this was a common problem with an above ground pool.

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Metal treatments are sequestering agents. They bind to the metal ions in the water and "deactivate" them so to speak. This effect will wear off after time. pH is a large factor in this. In theory, as the metals fall out of solution they will precipitate in your filter but in reality they usualy do it in the pool. Copper will cause blue or blue green staining. Sorry to say that copper(like herpes) is forever. Anyone who has ever kept salt water aquariums knows this since copper is deadly to salt water invertebrates and is used to treat fish only tanks. Using Aquariums or equipment for invertebrates that have previously used for fish only tanks can prove deadly for the animals even if they are thoroughly cleaned! I have over 30 years experience in SaltWater aquariums and have seen it happen time and again!

It just means that you will probably have to use a sequestering agent in you pool when the green color returns. Not that big a deal.
As to how it got there--if you used an algecide to kill the algae it might have been copper based.

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Originally Posted by Lschaal

I only used chlorine to treat the algae.

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Whatt type of chlorine are you using? Before the board went down Ben had a post about one company putting copper into their chlorine tabs and calling them "double duty" to supposedly help fight algae. I am not saying your problem was definately caused by copper but a clear geen color appearing in clear water after a shock does sound like a metal problem and the fact that a seqestering agent solve it tends to confirm the suspiscion.

I only use liquid chlorine. I also have used super algi-gon, it's active ingredient is didecyl dimethyl ammonium chloride- 50%. The metal remover I used was Metal Magic from ProTeam- 32 oz in a 22,000 gal pool. Do you think I should add more or just wait and see if it turns green again?

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Originally Posted by Lschaal

I only use liquid chlorine. I also have used super algi-gon, it's active ingredient is didecyl dimethyl ammonium chloride- 50%. The metal remover I used was Metal Magic from ProTeam- 32 oz in a 22,000 gal pool. Do you think I should add more or just wait and see if it turns green again?

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I wouldn't add anything else until you have a problem again. If it is metal that is the nature of the beast. If it's not metal I am completely baffled. Looked up the MSDS for the algecide and it's a linear quat. Biggest side effect is foaming. According to Ben the best algecide to use is polyquat but if you have an algae bloom shocking and maintaining shock levels until it is gone is the best way to treat it.
Other source of copper that is most commen is pipes used in heaters or in your fill water. Does your house have copper plumbing?

I think we do have some copper piping under the house. But what is most confusing to me is why now? We have had the pool for almost 4 years and never seen this before. I am guessing it may be something that builds up over time. Thanks for your thoughts and advice!!:)

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Originally Posted by Lschaal

I think we do have some copper piping under the house. But what is most confusing to me is why now? We have had the pool for almost 4 years and never seen this before. I am guessing it may be something that builds up over time. Thanks for your thoughts and advice!!:)

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It is something that will build up over time and whether and when it shows up is mainly dependant on pH and the amount of oxidizer in the water. Good luck and don't loose too much sleep over it. At best you now have free algicde in the water!