heat and acrylic tanks

[PerfectRapture04]

I've got a 15 gallon acrylic tank with two 65 watt pc about 3 inches from the surface. I have a fan blowing cold air into the hood, but I'm having trouble keeping the tamperature below 80. Is it possible that the lip around the tank is preventing proper evaporation, or is it possible that acrylic holds heat more than glass. I was wondering if cutting the lip on the tank would increase the surface area. Any ideas?

[PerfectRapture04]

any ideas???

[m1a1fan]

Acrylic is a great insulator. I wouldn't cut the lip around the tank. Is it possible to try a slightly larger fan? Or worse case lose the hood all together and suspend the lights above the tank. You could also use an Ice Probe type electronic chiller.

Just a few ideas,
RC