Hi Everyone, I have a 29 gallon tank that has had persistent cloudy water for well over 10 weeks. It seemed to go cloudy when the weather changed from summer-like to fall. This tank was set up in March of 2009 and after it's original cycle was crystal clear until September of this year. Here are the water test stats: Ammonia: 0 Nitrate: 0 Nitrite: 0.3 (at the last reading this week. Varies between 0 and 0.3) pH: 7.2 GH: 6 (Hardness) KH: 10 (also hardness as tested with my Tetra Laborett kit) Temp: 78 All the water comes from our well which has tested ok for drinking quality. Filters: The original Walmart 20 to 40 gallon hob Aquatech that came with kit and a second aquatech hob 5 to 20 gallon filter that I had on hand for extra filtration since it wasn't doing anything else. Added 3 weeks ago a tetra 2 to 15 gallon inside tank filter that we moved from a 10 gallon tank. I have decided that the wally world filters aren't handling matters and added an AquaClear 70 last week to eventually replace all the other filters once it is established. The original filters are still running right now along with the AquaClear 70. The filter media is changed according to instructions or if it is clogged and I only change one filter at a time. I can say that the Aquatech 20 to 40 hob media clogs in about a week to the point that half the water is going over the bypass. Inhabitants: 3 tiger barbs, 3 neon tetras, 2 paradise gouramis, 2 black mollies, 2 black high fin tetras, 1 6 in pleco, 1 6 inch red tail shark, 4 small guppies (school project refugees) , 1 kuhli loach, 2 upside down glass cats, 2 albino cory cats (refugees from a cichlid tank), and 2 chinese algae eaters. All these fish except the cats have been in the tank since early summer. The pleco and red tail are the oldest residents. All the fish seem to be perfectly happy. I did lose a Walmart neon gourami about a month ago but there didn't seem to be anything special about his death - just natural causes. I added the little catfish and algae eaters about 2 months ago as an attempt to help eliminate uneaten food. My kids were also feeding a lot of shrimp pellets to the mollies (who are real pigs lol), but we took the pellets away, along with the rest of the food and got that under control so they are fed once or twice a day. We even added a glass dish to drop algae wafers in for the pleco to help stop food from spreading. I had one live plant in the tank and pulled it about a month ago, but that changed nothing. I have no idea what sort of plant it is any more - just some short stalks with leaves on them. It now is in another tank which is perfectly fine. Thought maybe there were dead leaves or something unser rocks causing problems. I have been regularly changing 10 to 20% of the water qeekly. At each change the cloudiness will reduce but returns full force in a day or two. The cloudiness is white and you can clearly see clouds of white microscopic "dust" in the tank. As a last resort I used Tetra Algae control but that hasn't accomplished anything either. My last move has been to remove all of the plastic plants and the smaller rocks and run that way. Everything is in buckets of tank water to hopefully not lose all of the bacteria. Nothing has been washed or anything like that. Hasn't seemed to help and no obvious algae growth. I would also note that we have a 10 gallon tank with two angel fish (3 or 4 inches long) and two little catfish that seems to have developed the same issues as of about a month ago. Also have a 5 gal tank with one yellow cichlid (the guppies used to be in it, too) that is beautifully crystal clear. Help! We really can't think of anything else to try. The LFS is clueless. Can you have a permanent bacterial bloom?