So this is my first ball and im having a hard time keeping the temps right in the tank...

I'm also not sure if the thermometers I bought work right or not. I got the cheap analog petco ones. the set up Is a 15 gallon tank, 10-20 gallon zoo med uth on the right, a 100 what ceramic bulb in the dome on the right also and both heat sources plugged into a zilla 1000w thermostat. He has a hide rock on the cool side, a hide coconut on the hot side and a tub to soak in. I have the thermostat set a little below 90.

My problem is that the thermometers say 85 and 80 all day and at night they drop to 80 and 70 which is too low right? should I get different thermometers? I really don't like petco. Lol

He stays in the cool hide during the day so I think that they might be giving me false readings.

If it's not the thermometers, how can I raise the temp?

Thanks for all the help!!!

This is the placement of the probe