heat and light

Question
I want to change my beardies' light and heat fixture to a mercury vapor bulb on a stand hanging over the screen to  his 45g critter cage. I'm not sure what wattage I would need. He is on screened playsand. Any sugg. would be great. Thanks.

Answer
 The most reliable mercury vapor light would be the Mega-Ray, which you would order from ReptileUV.com.  The developer/owner/distributor known affectionately as Bobmac is available by phone to customize lighting to your specific set-up.  I would also reccomend investing in a UVB meter to measure the UVB output of your bulb so you know when to replace the bulb, because unlike many other brands, the Mega-Ray often produces good UVB beyond the six months usual decay time, and that is a signifcant savings in the long run.  I personally have had these bulbs last near a year emitting great UVB.  Other brands I have used have pooped out in 3 months.