Use whatever keeps the temperatures at the correct levels and use them all the time. If it's a red light lamp, it won't hurt to have it on at night too.. just keep an eye on your humidity levels.
I use a red lamp but ive found that by positioning the lamp partially over the water bowl it gives him a basking spot and creates humidity. it could be wrong but like ive said it seems to work to keep my humidity level around 55-60%if someone has a better method let me know
"It was 4 in the mornin 22 degrees outside of course you weren't there wussy"
I have to use both, and I too position the lamp over the water to increase the humidity. When there is an impending shed, I add a second bowl to bump up the humidity.
Rats in the hold. Crew is dead, I fear the plague.....