Aquarium heater question

Have a mini fridge that I have set up as a ferm chamber with a Johnson temperature controller for cooling. My basement is about 64 right now but gets to about 59 in the winter. I want to set up a water bath with a submersible aquarium heater to control the temp. Can I plug the heater directly into the temp controller like a fridge or does it require
Additional steps.

You want to be able to warm your mini-fridge from 59 to a little higher (ale temps)?

You could get away with the smallest aquarium heater you can find, and you could plug it directly into the temp controller, provided your controller has the ability to do heating as well as cooling (not all of them can do this).

Yeah I want to take the controller off the fridge and submerge the heater into a water bath and use the controller to set a desired temperature

I've seen alot of posts on here where some people say you can submerge the temp controller thermometer and some people say you can't. Any particular reason I can't? If not how else does everybody control the temp of say a water bath controlled with aquarium heater

I have several temperature controllers from Chi Company. Their temperature leads are soldered to the wire that goes to the controller itself. It is the only metal that is in the water when I use it (the carboy and aquarium heaters are glass and the trash can is plastic), so no galvanic corrosion.

I haven't had any problems with it, but it is somewhat fragile, and I avoid messing with it once I've got it hooked up and dialed in.