Would you rather run a 250 watt halide on your tank for 6 hours OR run a 150 watt halide on your tank for 10 hours?
150 for 10 hrs
Would you rather run a 150 watt 10k bulb or a 250 watt 20k bulb?
250 watt 20K
The heat issues scare me. (especially since I don't have a thermometer)
It really shouldn't be a problem. Fans will fix any problem you might encounter. If you don't already have an auto top-off I can build you one, cause your going to evaporate lots of water. Adam, a thermometer is like $3, it's a good thing to have.