I have a 55 gallon tank with 1- 5" oscar, a 3" oscar, a 5" managunese, a 5" clown knife, a 3" mecaw cichlid, a 7" red tail cat, and a 9" pleco. ive had the tank set up for about a month and i cant get it clear. it has a white cloud threw it. all my levels are good exept my nitrates i cant get them down. i dont think i over feed i try to let each get 2 goldfish a day. ive been doing daily water changes to get the nitrates down but it wont stay down. i dont know what else to do???