I am new this is my first post. Also this is my husband and I's fist salt tank. Have had no problem thus far water perimeters have been normal no change my husband checks them so I don't know the numbers. We have a pair of clowns, hawkish, basselet, and two recent adds (1month ago) were a yellow golby and wrass. Only thing I have noticed different is my clowns have darkened I'm not sure if it was because of the added fish. I read they can change colors as they mature. So the problem is my neon polyps has been doing great been growing and then was always open for around a week then last 3 days it's not opening and this brown stuff is starting to cover more of it. Not sure if it's algae or if it waste that the polyp is getting rid of or if it's disease. Should I try wiping it off?