Monti swollen and blistered

[CharliesReef]

Hi

Please can anyone spread some light on what's wrong with my Monti?
They started with swollen and blistered tips a few days ago and now it's the entire corals, it's not all my Monti and no other sps are effected including several species of Acropora, pocillopora, Porites, Pavona decussatus, Seriatopora guttatus, Seriatopora hysterix, Stylophora. They look fantastic which is why I'm so confused.

Id Increased my KH/Alk about a month ago and started using some different foods one of which causes a Phosphate spike to 0.30 which I've been reducing.

My water parameters are as follows
Calcium 350
KH/Alk 11.2/3.99
Phosphates 0.10
Magnesium 1300
Nitrates 3
Ammonia 0
Nitrate 0
pH 8

I can see the flesh on my Monti capitata looks to be peeling off now, so fear the huge red Monti cap which dominates the tank will do the same.

Not sure how to post photos from my iPad, just working it out.

 

[CharliesReef]

Photos

Photos

 

[nereefpat]

I wouldn't keep alk that high. 8-9 might be better.

I would increase Ca 50 ppm or so. 350 is low.

Possibly the Phosphate spike affected it.

How long have you had the Monti?

 

[CharliesReef]

I wouldn't keep alk that high. 8-9 might be better.

I would increase Ca 50 ppm or so. 350 is low.

Possibly the Phosphate spike affected it.

How long have you had the Monti?

Thanks for replying.

I had them over two years from tiny frags.

I'm leaning towards something environmental, kind of hoping someone else has experience with sps creating bubbles throughout their flesh. Phosphates spikes have happened in the past without any side effects other than some increase glass cleaning needed. My KH/Alk is higher than I usually have it, but it's been a month at increased level and was increased slowly. Usually I'd get some STN if I see a swing. I'm bringing it slowly back down again.
I removed some Clownfish short time ago, they were so messy and constantly had debris in the water column, now it's crystsl clear and can see the lights penetrating much better.
I do know light it part of the catalyst because when I reduced lights the bubbles reduce, lights off and there is no sign. But if it's too much light I'd expect burning, bleaching or polyps close up which is the normal reaction?
Agree it's probably something chemistry wise is causing the reaction. It as if photosynthesis by the algae in the coral is over producing oxygen and it's not passing through the flesh like it should so getting trapped bubbles. It's crazy odd, just hoping someone else has experienced it and new the cause for sure?