hnkthetank,
i understand completly about the heat problem - i have a jbj 12 gallon nano with a heating problem - well not as bad now anyway..............
i took two (2) vegi clips and clipped them to the upper rim - suction cups facing outwards .... and rested the hood on top . leaves an opening for more heat to escape and not so much light to blind a person also. works pretty good anyway and i was able to drop my water temp down 3-4 degrees. changing your light's on time as Laddy said is also a big factor also.
my tank is really comming along now and i wish i could get my camera program working again to post a few new pic's,,,,,,,,,,darn adware got me ....arghhhhhhh.
take care
M..........