Ok, I am doing a horrible job at making myself clear
My 10 has a heater, my 15 doesn't
I bought a heater today that's rated for 10 gallons, the one on my ten is rated for 15 or 20.
I want to put the heater FROM the 10 TO the 15, and then put the new heater on the 10, so that both tanks have heaters. I guess I got impatient though, and currently Poe (my Betta) is in a 1 gallon bowl while the water in the 10 gets back up to his preferred temp of 79

Thanks, and sorry if I sounded angry or anything,
Cory