Keeping temp consistent

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!!!

Seven degree swing both ways is a lot. It helped a lot when I insulated the outside three walls on mine and put foil on the top and blocked about 85% of the top. My temps have been pretty constant since.

For my big boa, I have two UTHs which has been working out pretty good, but you shouldn't need two for a 20g.

75* isn't really too bad for the cool side.

You could get another UTH the same size as the one for the hot side and plug it into a rheostat (lamp dimmer) and then into the reptitemp 500r. That way you can maintain a cool side temp as well as a hot side temp at all time without having to worry about room temperature fluctuations. As long as the ambient temperature doesn't go below 75*, you will be fine :)

The UTH should cover somewhere around 1/3 of the floor but no more than 1/2. Moving the UTH to the bottom should stabilize your temps out. Since heat rises, by having it mounted on the side, all of your heat is staying concentrated on the end and not being radiated throughout the substrate and enclosure. If you are using aspen, cypress, etc, type substrate, make sure you only have it about 1/2 inch thick or so over the UTH to allow for the heat to radiate through. If the substrate is too thick you will have the problem of the temps on top of the substrate being too cool and the temps under the substrate being too warm. If you are using an Accurite or other thermometer with a probe then set the probe on the glass, under the substrate, adjust the repti-temp until you get a temp of about 93F on the glass surface, and then adjust the thickness of the substrate to get the desired temps on top of it...