T8 bulbs are usually 34 watts. Should work okay if your Ballast is
electronic start.

DJay
wrote in message
oups.com...
I have a t12 25 or 40 watt shoplight fixture (48 inches) on one of my
tanks, is it true I can use t8 bulbs with it as well (I am assuming the
t8 bulbs would be required to be 48 inches long and 25 or 40 watts in
power)? Please confirm - thanks all!