Incandescent lights do raise the water temperature, and I wouldn't be surprised if it raised the temperature closer to 85 degrees. When the light turns off, that is a big temperature swing for the fish, even if your heater is set to 80 degrees. I had a hood like the one you linked and it came with normal output tube fluorescent lighting. That would be a better option for keeping the temperature stable, but you would be limited to low-light plants - crypts, java ferns, anubias. The moneywort probably wouldn't make it under the fluorescent lighting that this hood comes with. I have heard of putting compact fluorescent screw-in bulbs into the incandescent hood. I'm not sure what wattage you would want - probably no more than the equivalent of 25 incandescent watts, since that's what the hood instructions say is the maximum wattage you can use. You would also have to make sure the bulbs physically fit in the hood.