It will definitely be low light. I have one with a 13w cfl and the plants grow really slow until they get near the top. They do grow though. One thing I would recommend is to switch out the filter as the one it comes with blocks a lot of light. I took that out and cut out a strip of plastic from the top rim which allowed me to put an ac20 on the back. I can take a picture tomorrow if you want to see what I mean. This is assuming of course that you're talking about the Marineland kit.