Enclosure Temp

[Bradmc]

Hi, I've got a just over 5 month old Russian tortoise and I recently built him a 4x4 table but I'm having problems with fluctuating temps. My apartment building tends to get very hot as the day goes on and this means the temp inside the table heats up quite a bit and I'm having to constantly raise & lower the basking light.
The temp in the morning starts at about 30c in the hot end but by the end of the day it could get up to near 40c if I don't raise the light.
Any ideas on what to do as obviously raising & lowering the light isn't a viable long term solution ?

Thanks.

 

[Kapidolo Farms]

Use a thermostat, all heating devices should be controlled with a thermostat. Here's an inexpensive one https://www.zenhydro.com/ipower-dig...0EXVAly9whhBUijai-sTcIHAKxjSi9CxoCl_sQAvD_BwE

 

[KarenSoCal]

As Kapidolo Farms said, using a thermostat would help, but then the "sun" will be popping on and off all day.

How about a lower wattage basking bulb? If it's ever so slightly cooler than recommended, it's OK. As the room warms, the temp will go to where it should be.