Millie tips bleaching

[subman]

I have a couple Millie colonies that I thought were showing good growth tips but they are now to long to be new growth. I have been struggling to maintain my cal and KH as Ive added massive colonies lately. So I was thinking it was ALK burn but my test this morning were: CA-390 (was down to 340 earlier this week) KH-6.7 (it peaked at around 7.3)
My Phosphates, nitrates, ammonia is 0

Im running the full zeo system, doising zeobac, zeostart3, amino acids and coral vitalizer, and k-balance.

I should add I have great polyp extension on all my corals and even the bleached areas have polyp extension.

I did have cheato in my sump but it has been shrinking lately so I took it out last night. Nick (titus99) told me it could be leaching out as it dies off, so its out now as well.