When I was a kid, living with my extremely tolerant parents, I had about 20 aquariums in my bedroom. The tanks were stackedagainst two walls and were three deep. I used nothing but 40 and 60 watt bulbs throughout. The heat generated by the bulbs rose up through the shelves and heated the tanks above, giving me a heated substrate. Several spp. bloomed in there, including some bog plants, i.e. water poppy.