I will say that a fair few cfls will be needed if you want a nice thick canopy of product but it can easily be done. Iv found that my 400w hps with a cool tube gives 50000 lumens as compared to 10000 using 8 23w cfls. So if yeild is what you want the hps is the way to go. I made the swap because i hate heaps of cables and mess and the cooltube does a great job of keeping things cool