New 40 gallon breeder check it out with question

Hey yall just had a few questions hope all of you can help.

1. After making the conversion i only have a 10-20 gallon for a uth and im going to get a 40 gallon uth but in the mean time i am stuck with that, but the question is if i have the 10-20 gallon on the right side of the tank should that be okay until i get the right UTH for the tank. Also on the right side which is the hot side it reads about 88 to 89 degrees buuutttt on the left side which is the cool side it reads about 70 degrees as well as the middle so

So i need some advice on how to keep the heat up. ALSO the humidity is at 65% so that is good. plenty of hides as well i will put picks in also

This picture is to show that i have digital thermos as well as a thermostat controller
http://i70.photobucket.com/albums/i9...s/DSC01880.jpg

http://i70.photobucket.com/albums/i9...s/DSC01881.jpg