I have this Bi-Color Angel for two weeks and it looks like he has black ich on one side on top, on the yellow side. He had pop-eye two days ago so I gave him a freshwater bath and it went away. I have a 46 gallon bow front acrylic with the reef octopus bh-1000 protein skimmer and an aqua-top canister filter. The other inhabitants are 3 scarlet hermit crabs, 1 orchid dotty back, and 2 Ocellaris clowns. There is 40 lbs live sand and 40 lbs base rock. Is this black ich? I also have a diatom outbreak any ideas on getting rid of it. I filled it with tap water(mistake) and am now doing water changes with distilled water. I've had the aquarium up and running for a month. One more thing how much lbs of live rock, do I need to make the base rock turn live?