Yes, you can. I've used 2x15W CF
bulbs in my 10G AGA economy hood before with pretty good results. I think I read somewhere on the forums that you can use up to 23W bulbs, depending on the size of the ballast and the size of your hood. Just bring the hood along when you go bulb shopping to make sure it fits. I did have one of the bulbs short out in the 10G hood though, so if your hood doesn't have a glass sheet between the bulb and light strip, it's something to watch out for.