Sure, its "ok". You'll have to try it to see what grows well, though. That's a pretty cool temp, though. Most macros are likely not to thrive. I think I'd try the 25w in a better wavelength first--more watts going into a light that can't be utilized isn't an improvement.
(I assume that you have a reflector to direct as much of the light downward into the 'fuge, right?)