To be honest, I'd change bulb, if that even creates half as much heat as a standard bulb, your plants will fry at 2 inches, burn at 5 inches.
I'd get a mini fluro, you can get them at any diy store in the uk, and I'm sure home depot or something will sell them in the states.
Also, from reading the boards previously, many people kinda slam special "plant growing bulbs" as being crap.
Only going by what I've read, but at least with a mini fluro your plants can touch the bulb itself and not burn.