I actually did the same thing with my eclipse 3 a few days ago, took of rim and hood, added small powerhead. I'm not using a heater, because the desktop lamp that I'm using for light gets the tank to a nice 75 degrees. If you lower the fixture a bit, I bet you could take out the heater... one less piece of equipment in the tank! It's really a peaceful little thing to look at, right?
You're in my heart, you're in my soul, you'll be my breath should I grow old