Just updating the journal that 2 days ago I upgraded powerheads to pp-15 from 8s. Maybe related or maybe not but a couple acros have browned and my favorite one has browned and reduced polyp extension and has hundreds of mesenterial filaments barely poking out of the underside all over it.
Don’t plan to do anything about it. Cross fingers that it’s just adjusting to the new flow. Powerheads are in same positions with no direct flow.
I noticed quite a bit of mesenterial filaments around the base of one of the new acros i got from battlecorals recently. I can only assume it's just part of the process of the coral acclimating itself with the surroundings. I'd wager the increased flow has the coral a little worked up. I'd think if it was healthy to begin with, it's probably just ticked off and will regain color and PE again. I know I've ticked off some sps in the past and it's crazy how they'll rebound. I've nearly killed a particular monti setosa a dozen times and it keeps coming back.