Ok, this has stumped a reputiable (hopefully I spelt that right) fish store. I purchased a 20 gal tank with a aquatech power filter and let it run for two weeks with no fish in it, at the end of the first week it began to get cloudy. I went to the store and lowered the ph to around 7. I let it run when I went on vacation and when I got back it was almost to the point where I could not see anything. I went back to the store and the manager was there. He said it may be the start up tabs made by jungle that I used in the beginning, so he gave me some water from an established tank to put in and said it may be healthy for the tank to put some fish in. I got 2 gold barbs, a trI color shark, a ruby shark, and a coby catfish. I put the water in and the fish and they seem to be fine but the water is still cloudy. It got a little better and then stopped. Can anyone help me get rid of this? I have pictures if anyone needs them to diagnose the problem.