get one of the compact florescent bulbs... the ones that are labled like Energy efficient or somthing like that. Here is a site for what they look like. they are not usually that expensive though. i have a good portion of my plants under just ONE of these. my D. capensis "Red" is getting darker and my D. alicae seedlings are also turning a nice red. i have it(it has a 60 watt output but uses only like...20 watts or somthing like that) over a 10 gallon tank.