Corn snakes and lighting

Question
Dear John,

Hello!  I have an elderly corn snake; we've had him since he was born in the fall of 1992, so he's 18 years old.

Yesterday I took him to a vet for the first time for a mostly "well baby" check, and to make sure that there's nothing I need to change as far as husbandry issues are concerned.  I keep a calendar with all his feedings marked, plus when he sheds, and typed out the list of dates for the vet instead of flipping calendar pages or trying to remember.  I've decided to add when he goes to the bathroom too, just for reference.

The vet seemed to be impressed, both with Spot's age and his perfectly good condition, his weight at 2.9 pounds, as well as his calm demeanor, especially when the vet was looking in his mouth!

The only thing he brought up is that we stopped using a "reptile bulb" in the heat light fixture over the warm end of the tank a couple of years ago, instead we're just using a regular GE 60w bulb for warmth.

If an official UVB reptile light will help Spot to attain longevity as well as retain HEALTH, I am all for it, but the vet didn't tell me any specifics as to wattage or UVB output, and most of everything I read indicates there's some doubt as to whether it is even necessary.  So...

Can you give me some guidance?  I can't afford a $40 bulb that I'll have to replace every 6 months or so, and don't know what to look for to make sure a $15 bulb has what my corn snake needs.  I use dome lights, so need a bulb that will fit in one of those fixtures.  

If it matters, Spot is in a 55-gallon aquarium with a screen lid, aspen chip substrate, and 2 hides.  One is underneath his water dish on the cool side, the other one is a half-log in the middle.  There's a red nighttime bulb over the water dish; the little heat it provides helps the water evaporate just enough to raise the humidity level so Spot sheds well.  The other side, with a 60 watt bulb, runs temps around 88-90*.

Thank you for any help or suggestions you have to offer, and for sharing your expertise on this web site.  It is greatly appreciated!

Sincerely,
Linda  

Answer
UVB is good but not a necessity from what we understand so far with snakes as they get their calcium through the bones of the prey they eat.  Also kudos to you for all the information you gave!  It makes answering questions here very rewarding when someone answers all the typical questions about habitat etc prior to asking their question.  You're doing a fabulous job keep up the great work!  Also if you wouldn't mind going to my website and leaving a comment with your email address I would like to send you the eBook on Corn Snakes we are currently working on when its completed probably next month.