1st time BP owner heating and humidity issues

[thejennabird]

I'm gonna ask you a few specifics to help pin down the issue:

I got him a 20 gallon reptile tank and the heating pad that is for that size.

How big is the heating pad? (Ie. how much coverage does it provide?). I ask because I've heard some of those "store brand" UTHs are technically too small and don't have enough wattage.

The temp wouldn't raise above 70 degrees in whole cage. I have thermometers on both sides and hygrometer in the middle.

Where are the thermometers located? Above/in the substrate or on the glass wall of the tank?

I put a damp towel over the lid which helps a little.

Have you seen this tank set-up tutorial? Tin foil and/or plastic wrap will do a better job of retaining humidity inside the tank compared to a towel because they aren't absorbent.

Now, very important: do you have a thermostat for your UTH? 70 does seem low, but how are you monitoring the temperature of the UTH itself (not the temp of the tank, the temp of the UTH itself?)