Ah, but this is a Caribbean reef tank, with Acropora not usually seen in most reef tanks [A. cerv.] ... which is always `golden' colored.
Nothing's going to make them green/blue/purple ... they don't come like that. I think there are a few Montipora in this tank [Pacific] so he is cheating ... but I bet there would be plenty of fools like me who would gladly trade any # of neon Acropora for a piece of one of these rare [in aquaria] brown ones.
But if you've spent much time underwater in the Carib area ... they're terribly beautiful as they're `home team colors', brown or not. Just my take, but like a number of things in this tank ... it makes me warm and fuzzy as it looks like the reefs I've been to.
But maybe I've only been to those schwag Carib reefs :lol: