My aquarium keeps getting cloudy and was wondering if anyone knew why. It's a 210 gallon. It's filtered by an fx5, an xp4, a hydro V connected to a 170 gph powerhead, 2 aquaclear 110s, and a green killing machine uv filter. Right now I have 2 oscars-8 and 9 inches, 2 green terrors-3 inches, 2 spotted Raphael catfish-3 inches, 1 flowerhorn-5 inches, 2 midas-4 inches, 2 red devils-4 inches, 2 pacus-7 & 8 inches, 1 convict-5 inches, 1 green texas-3 inches, 1 green sunfish-5 inches, a jack dempsey-5 inches, and 1 pleco-7 inches. I know all those fish won't work together in the tank long term, so I'm going to move some around to other tanks. Right now I don't think they'd be making too much bioload for my filtration to handle and causing the cloudy water. I do about a 50 percent water change every Saturday. The water looks a lot clearer right after the water change and for a few days. I hav e play sand for substrate. I have stirred the sand up after a water change before to see if that's the problem, but it doesn't seem to cloud the water up. Any thoughts would be appreciated. Also if someone has an opinion on which fish I should keep in the 210 I'd like to get your idea. I also have a jag that's only about 2 inches right now I'd like to put in there, so take that into consideration. Thanks.