Yeah I think in the top will be two 4" fans. Is that too big of fans?
too big
This is what I am getting ready to put on my sons 37g
canopy. I am going to use 3 or 4. They only run $15 each
Thermaltake ISGC Fan 8" Cooling Fan - AF0043
The air flow is about 25CFM and they have to be modified a little because they are DC current
Just remember that if you install fans, make them PULL the air through. air doesn't do well being forced into a space (unless your feeding it into a cars engine
... but thats another show
) ...u get a compression effect.