Do you recommend anywhere to test for copper? Or a specific test I can do at home? Does it even matter what the number is when you already know it's in the pool and has to be drained anyway? This is a "left over" problem from using Algaecides last year - pre TFP knowledge. I really thought from all the back washing and refilling over winter (lots of rain) that this would not be a problem this year. Ugh! My poor blond son is showing his inner green alien after only a few swims. His hair is not terribly green yet, just a slight tint. Thanks for all your help!