the internal ballast will only handle 30w bulbs. To get more light you will have to change the fixture or get a retrofit kit that will fit into your existing fixture. Your best bet would be to get a 30" pc
fixture Or a vho
prices are coming down so if you keep an eye on ebay you might be able to get a good deal. I got a 24" jebo pc
with 130 watts for about 50 on ebay.