Ya i was just wondering about the fading thing because my buttons really faded big time under my pc lights. I was never sure if i had to spot feed them or not, and i never really did consistantly so that may have been why mine faded. idk.
But they're a sort of mat you say? Is it like a solid mat or is there sort of gaps in between some of the polyps at some places. Either way i still think its what i said before...my big button colony was pretty solid (the mat i mean) with very few gaps here and there.
Not sure how the moon polyps grow tho, because when i glued mine in...i didnt glue them all in the same spot. I put them all on one piece of branch rock, but i spaced them out a lot, so theres already gaps. Now i cant tell which ones i glued or not, but they seem to be starting to grow a sort of mat thing.