UTH and mercury vapor?

OK first timer here. I set up the UTH and are considering mercury vapor bulbs. Could I use the bulb during the day and use the UTH at night on a timer?

First off MVBs get really hot and you cant dim them any way or you will kill them. Why are you wanting to use a MVB on a snake? I have used them on lizards but never snakes and in the end I went back to just a heat lamp with a ReptiSun 10.0 T5 for my lizards. And yes you can use them during the day and a UTH at night assuming your ambient temps stay around 80F+. A UTH is not going to heat the ambient air. Honestly my advice is instead of spending $80 on a MVB, just buy a heat lamp for daytime and a CHE for night time and then just leave the UTH on all the time assuming you like it. I just use CHEs only with no UTH and my house is kept around 75F and it works fine. And of course you need a T-stat for all this except the MVB since you cant dim them or change their voltage at all or you will kill them and/or cause them to turn off and do a 15 min reset.

Why use any bulb at all? Ball pythons don't need UVB so why use a mercury vapor?

I keep and breed so many snakes and all they have is a uth (heat tape for me), unless the temps drop below 75, then I use a space heater. They eat, sleep, poo and breed no problem.

I presume this is for a ball python and not meant for another forum section?