Temporary high phosphates for SPS?

[Aquattro]

My 150 went from 80 to 89/90 daily for about two months during a summer when my chiller died. The fish all did fine and on the hottest day (91), I lost all of one species (5 different pieces of it throughout the tank), but nothing else. I probably lost some of my lifespan stressing about it, but the tank did fine. I wouldn't recommend it, but going to 84 shouldn't hurt much, unless you have a huge fish load. Then O2 might come into it. But if you've got good surface movement and a good skimmer, O2 should stay in the safe range.

As for PO4, I would expect a sudden shift in levels (either direction) might not be really good.