Rule of thumb is 4 watts per gallon. So 40watts would be good, any more would be great. So you are right there with the lights you have if they are PCs. But it really depends on what kind of stuff you would like to keep. If you are looking at keeping some lower light corals, PCs would be your best bet and your good to go. If your looking to keep corals that need a lot of light, you could go with something like this. http://www.marinedepot.com/md_viewItem.asp?idproduct=JB9111
