I have 4 tanks ,120.90.180,200 gallon all tanks are crystal clear except for the 200 with a eheim 2262,2260,2 aquaclear 110 and a sump system doing 1200 gallons.Just added auto water feed changing 48 gallons a day.I have 3 clown knifes,giant gourami,sailfin cat,bichir and a pleco.Tank has bare bottom.any ideas why water does not clear up.