As far as I've heard, the ambient temps can be 82F, but it could bring the res temps up which is not good.. I do know that guys have thrown frozen bottles of water in their res to keep those temps down, but have you tried having the fans blowing more at the T5s?? If not, it may be something to explore.. My enclosure has had several days where the temps went up to around 82F, but the plant seems to be doing okay.. Like I said though, your plant is far more full than mine, but I think as long as you're not going a lot above that and your res temps stay low, then you're fine..