I've got a 180gal tank with 1 FX5 and a 40 Gal. sump. The tank has 6 RBP, 6-8 inches, and 2 plecos, 1 6inches the other 14inches. I do not feed them too much live food. They get alot of Massivore, hikari Gold and Fillets. However when I vacuum( every 10-12 days) the tank is filthy. I can't see thru the vacuum tube? Normal or Am I missing something??