I have ahsupply lighting on 2 of my tanks. On both of them, I installed
a 3" fan to help with the cooling, in addition to placing the ballast on
the outside.
Daniel
"Shawn P. Good" wrote in
:

Hey Dave .... thanks for the tips. My ballast is mounted on the
outside of the hood. The plastic light hood that I retrofitted alread
has 2 vents in the top about 4 inches long. The retrofit kit came
with 2 one-inch diameter vents to install if my old hood didn't have
vents. But since it already had the vents, I didn't install them (I
also do not have a 1-inch drill bit) but now seeing the heat this baby
is throwing, I might buy one and put them in. I also might try the
foil insulation material as suggested by Red Foreman.

So far so good though. The plastic seems to be holding up after 3
days, with the lights on 12 to 14 hours per day. I plug it in when I
get up (7:30 am and turn it off when I go to bed around 10 or 11).
And my tank has never looked brighter. I hope my swords come back.
Their leaves are looking a little translucent and brown .....

Shawn