Guess what we have? Crystal clear, almost blue water! I can't thank this forum enough. After reading, listening, learning, and asking questions, I have finally figured out how to take our new endless pool from an opaque molten grey mess to an ever improving, very inviting crystal clear blue, with just a slight tinge of green, which I am sure will soon be gone altogether. Lessons I have learned... First, don't trust the pool stores at all. I went to three different ones and all they did was pile me up with more and more expensive chemicals that just made things worse. Second - kiss (keep it simple stupid). It's all about chlorine, PH, and patience - and in my case, metal sequestration. Third - if you have a cartridge filter, don't EVER put DE, cellulose, or anything else in it. Just be patient and let it do it's thing. Fourth - if you have metals, and copper in particular, don't used Nature2. It just adds more copper and it's easy enough to keep the pool sanitary with liquid chlorine alone. Fifth - bring your questions here. These folks have no agenda other than to help one another by sharing their experiences. Thank you again to those who helped me!