Perfect. That is what I figured. I did some research on them last night to get a better idea of them.

And a GFCI were my first thoughts on it. Every time I put my hands in my sink with two $10 chinese heaters, and two $5 chinese pumps, I was always wondering if it would be the last thing that I ever did.

I have noticed you can wire an alarm or indicator light in to them to come on when the temperature is below threshold. Pretty slick.

I plan to use an oil heater or water heater element for my baths. They can be removed easily, do not require soldering, and usually have their own rubber gasket and lock nut. And I have no idea what developer, or fix, etc. will do to them. Especially the pumps. So making everything easily replaced is important.

One in particular that I am looking at is 4kw. Meant for much larger volumes. Do you think it would be a good idea?