Even with clean media in my canister filter, the water is not quite as clear as it should be. I know diatom filters get the water crystal clear and I would like one, but is there any very very fine media I could put in an in water filter which I put in the aquarium sometimes after I have been cleaning the gravel. I don't run this very often, so was hoping I could find some sort of super fine media just for final cleaning on the water.