heating pad for water tank

[metropical]

have a CA wood turtle in a 50G Rubbermaid stock tank.
There are 4 lamps above. A ZooMed daylight, a basking A21, a ZooMed night bulb and florescent ZooMed UVB.
Within that is a smaller 16" diameter 4" high tank for water. It's made of ~1/2" thick rubber (or very flexible plastic).
He spends a lot of time there, which is fine. But I think winter is a bit of drag for him as the house is prolly only about 65ºF on average.
Any suggestions for a heating pad to go either in or under the 16" water tank?

 

[Yvonne G]

If the water's deep enough you can use an aquarium heater but it must be protected from the turtle or he may break the glass.

Also, if you cover the tub it helps to keep the heat from the lights inside.

 

[metropical]

no water isn't deep enough. Thinking a pad underneath.
Was thinking something like this.
pad

 

[metropical]

this is the tank and turtle.