The 250w is going to produce even more heat obviously. FWIW I have 2x250w MH
10" over my 55 gal
w/ 20 gal
sump, two fans mounted in the canopy and if room temp hits 82+ deg. I have heat issues. My tank will easily hit 86 deg. on a day like that. It runs at 82 deg. with just the heat from the lights, no heaters on. MH
get extremely hot.
and should i run a new 15amp 120volt GFCI recp?
It may be a good idea depending on how much other equpment your using . If you don't already have a GFCI I would strongly suggest using one.