this is a pic of my zoas i had a diatom problem not serious...in the pic i think you can see some on them they seem to like to cover them.... about a month now they have been looking like this....i tried moving them a couple times over the month any idea's??? like i said before i had a diatom problem my alk and ph were low i got them both fixed...i have CF lighting is that not good enough for them? this my first zoa so i'm not use to keeping them any help i'd be thankful for