I wasn't sure which forum to put this in: algae or corals. I have this reddish colored algae that is seemingly eating my acans one by one. I pulled two acan frags and dipped them in seachem reef dip followed by Revive. I then moved those two to a new tank and they seem to be recovering (they were my rainbows). I have two other frags in my tank that are on larger rocks and they are now being attacked. Pics is attached of one. Kind of hard to see. My main concern is 'what is this stuff?' I've been doing regular water changes but my last two (when the algae really started to take hold) were done when my RO/Di filter was in need of a resin change (PPM read 200). Could that affect it? I know my nitrates are pretty close to zero. My nems are thriving. I'll check alkalinity and calcium and post it up. If I need to test for anything else, please let me know. I will if I have the kit. Thanks all.