What I saw at Home Depot were incandescent plant lights. I just told my friend to stick one over his 40 gallon for his Java Moss/Java Fern. It was much cheaper and probably a decent option for the low light needs. I just have no proof that it's enough wattage for the plants. I would guess yes. As far as heat goes, on a big tank like that, it probably won't have too much effect. Plus the office temperature where the tank is kept is maintained pretty steadily.