Retro fit or pendant?

[luvreefs23]

I have a 90 gallon tank with a 13 inch high or so canopy and was wondering if it would hurt to put a pendant style lighting system under the canopy instead of a retrofit kit. Im looking at this system here:

Ocean Light T5 MH combo - Aqua Medic

I want either the 36" 2x250 watt system with the t5s or the 48 inch system 2x250 watt with the t5s.

I was told that they wont breathe well in a canopy and they will work but may fail earlier due to heat and moisture building up in the aluminum casing. I have to fans...1 sucks in the canopy and one pushes air out. The fans are 4.5" 106 cfm a/c fans, put out quite a bit of air so i was wondering if they would indeed still get hot a fail prematurely.

Thanks