Hi Paul,
Thats about 110 gal here..a general rule of thumb is 3-5 watts per gal for a fishtank heater. If it doesnt get too cold where you are you could probably get by with 3 watts.. 5 watt is good otherwise...
I use 500 watts in my 125 gal tanks... but in the summer 300 watts works well for me.
Getting an external controller is a good idea if you can. Several people here use Inkbird controllers.
Hope that helps,
Al