Steve:
As long as the air temp in the room stays under 78F, the temp in the tank doesn't get over 84F.
Cheese: Exhaust valve from 89 Honda. I also have a rotor from a wankel engine out of an RX-7 I used to own, along w/ a fan blade out of a pratt and whitney turbofan, a milled aluminum propeller (4') long, a nut and bolt from a hydraulic tail goosneck trailer (can be seen in the picture beside the valve), part of a composite body panel from a Citation X and sundry other paraphenalia from my tinkerings and my professional life.
Moe_K:
Made them myself, but neither is finished.
Circa:
Don't know how many pounds, but it probably anywhere from 160 to 200 lbs. The liverock is 270 lbs fiji on a pvc frame so it looks like there is more than there really is.
Lighting: 2x400W iwasaki 6500K and 2x96W PC actinic (but one bulb burned out after the first month!) I will be adding a third MH lamp and two more 96W PC actinics.