OK, a few things brought to you by
http://www.reptileuv.com.
-You CANNOT dim MV lamps. They simply will not work.
-T-Rex and Mega-Ray SB lamps are indeed manufactured by the same company. The Trex SB is a copy of the Mega-Ray SB. Both are excellent lamps.
-Neither the Trex or the Mega-Ray SB lamp will project significant UVB to 6-feet.
-Mega-Ray SB Zoo will project up to 6-ft, but you need to be "approved" to order it. You also need to own a UVB Meter.
-There are no Mercury Vapor Self-Ballasted lamps lower than 100-watts. The technology is just not there yet. The starting wattage for SB MV lamps is 100-watts.
-Follow the link that Frozenlava provided and read all about UVB lighting for reptiles. It is the most accurate, up to date info you can get on the net.
;-) Read the MV lamp study and see how Powersun compared to the rest.
Frozenlava- Welcome to the Herp Center Network. Glad to have you here.
Dudeamis- Welcome to HCN. You can always call or write to ReptileUV with your set-up specs and they will help you decide which lamp is right for your particular needs (try THAT with Trex, LOL) Go to
www.reptiluv.com, look on the Contacts page and either e-mail or call Bob Mac. He's always glad to help!
Good luck with setting everything up!