I'm making the switch from CFLs to a Metal Halide lamp. I just bought a MH bulb and tried to put it in the fixture I've been using for my CFLs, but even after giving it a good 10 or so minutes to warm up, nothing happened. I did a little searching and found that I can buy a MH fixture, but they generally cost more than $100, which is just a bit out of my price range for growing a single plant. The fixture I have is rated to 150W and I'm using a 100W lamp, so I'm not entirely sure what the deal is. Do I need to purchase one of these expensive fixtures to use a MH lamp, or is there a cheaper alternative?