Quote Originally Posted by anbesol
87.6 F . I figured thats the best im going to do now. i have a 4" duct coming out of the homebox to pull cooler air from around the room..

What kind of Improvements do you think i will have with the HPS compared to the T5?
Photosynthesis is most effective around 78 degrees and typically you don't want to go above 85 degrees unless you're running CO2.

It's hard to say if there will be any improvement. I'm sure you were running cooler with the T5's probably. What kind of fan are you using to exhaust your cool tube? What is the ambient temperature where you have your grow (the temperature outside the grow environment). I only have 1 inline fan on my cool tube, 1 end open, ambient temperature of 76 and the temps in my box never rise above 78 with my cool tube 4" away from the canopy.

I am running a 400 watt MH/HPS at the moment.

To be honest I would pull your cooltube about 6" more away from the canopy. Put it about 1 foot away. The lumens aren't doing you any good if your photosynthesis is crawling.