I have a 55 with two clowns, live sand, and live rock, and have been running for about 7-9 months now and I’m just wondering if I should be worried about the red spots “I’ll link the picture.” Just trying to catch it before it gets out of hand
Yup, very likely coralline. If you have put a snail in there or any hard surface critter it likely has some even if it is not visible. It only takes the tiniest bit from somewhere, anywhere to get established.