Replace the mercury vapor bulb with a 65 watt incandescent flood bulb from the hard ware store. Adjust the height of the basking bulb according to what your thermometer says when directly under the heat lamp for an hour. Move the basking fixture over to one side and hang the CHE over the middle. Put the probe from your new thermostat over on the side with no heating elements or bulbs, and hang it down low just out of tortoise reach.I'm not sure I'm in love with this light fixture setup I have to regulate heat. I have 1 200w fixture with a 100w mercury vapor bulb and another 250w fixture with a 150w (I think) CHE. What is a better solution with a thermostat to regulate heat that won't break the bank?
I see that mercury vapor bulbs are not ideal, but because I completely built the wrong habitat I'm going to have to prioritize the corrections as I can't afford to re-do it all at once right now.
For UV, take the tortoise outside and give it access to sunshine in a safe outdoor enclosure. Make sure there is always shade available. Do this for an hour or two, two or three times a week. Soak after sunning. You can buy a UV bulb in the fall when temps begin to cool and taking him outside isn't as easy.