Thanks so much. I'm using a very low watt under tank heater with a small spacer. His temps are in the mid 70's. I have set up his 10 gallon and am check temps before he goes in it.BTW, Christyk, your baby turtle is very cute.
And now the lecture.. be very careful with heaters and small water volumes/levels. For the 5 gal tank, you cannot use a standard aquarium heater - that will cook the turtle. Instead, try a betta tank heater, which is a small heat pad. Always use a thermostat. Amazon has many inexpensive ON/OFF thermostats that work. Many are sold for seed germination - those are just fine. So a small heat pad and a thermostat will allow you to heat the low water level in the 5 gallon very easily and safely. Good luck.