Hi. Had a friend get me into saltwater aquarium...then he stopped talking to me(lol), so I need some advice on some things. I have a 40 gal long,crushed coral bottom, yellow tang, pygmy angel, 2 turbo snails, 1 zebra snail, 1 arrow crab, 1 damsel(small). I have an Emperor 400 bio-wheel(80 gal) filter, and a Cascade 35 gal filter. On Thursday, 6/15, I noticed a slight cloudiness to my water...Friday I couldn't see my backdrop. I changed the cascade filter, and one of the Emperor filters, and a 15 gal. water change. No help. Can I get some advice please?