The temps in our 20long tank are all over the place;

Currently have a 10-20 gallon repti therm uth, it is on the side of the tank, but I am planning to move it to the bottom. I have ordered a Zoo Med ReptTemp 500R Thermostat Remote Sensor for Reptiles

The hot side is ranging from 97-90 and the cool side from 75-82; depending on the weather/if our A/C is on.

97 is pretty warm, right? so I don't think I want a bigger uth for that.... but 75 is too cool, should I get another small uth and put it on the cool side and keep the therm set so it doesn't get above 82?

will moving it to the bottom help? I am waiting for the therm, since my temps were getting high 90's I didn't want the snake to burn. the therm should arrive today or tomorrow.

I'm not sure just what I should do to keep the temps where they should be on each side; it seems like when one side if good, the other is not or vise versa!

Thanks again!!!