How much heat from lighting is ok ?

[Rmckoy]

I run a diy t5ho fixture with 8 bulbs , 54 watts each over a 4’ long 90 gal tank .

I have a heater in the display to keep temperature above 78°

When the lights come on the temp raises to 80°-81° by the end of the light cycle .

How many degrees is safe to fluctuate throughout the day without causing problems ?

 

[jda]

That is fine, but I would not let it go much higher.

A simple fan will probably keep that from moving at all. I use Vornado fans that you can easily find at home depot or most any store this time of year... they are powerful and effective. Even with many Metal Halides, I rarely have to move them off of low or even medium on the hottest days.