Thank you so much! Glad to read that I am surrounded by pros! I have to say that it is impossible to imagine the water currently in there being anything more than sludge.

I have gotten 2 covers in the past. The first was basically just a tarp (although toted as a pool cover). It got so filled with water, leaves and sticks that it tore and everything slopped into the pool. The second one had small holes throughout that let the water through, but I think it was poorly made and just ended up tearing.

If you know of a good brand for a cover, please let me know. Also, I can't conceive of keeping the water clean in the winter when I can't even keep it clean in the summer.

I will drain it this weekend and start over - just to be safe. I'll get the test you recommended and then post my results. Should I use this thread, or a new one? Thanks again.