And yeah, the PC Rainbow is definitely letting me know.I've seen this in my corals. In my case, I think the issue was too low nutrients combined with high alk and bright light. Any time I get close to 8.0 alk, I see some white tips with the filaments. It looks like a sign of distress, not happy corals with growth. Interestingly, my PC Rainbow is the first to show it, and if I'm not mistaken, you show a pic of the same coral showing the same traits. Possibly take your alk down closer to 7.0?
