Mash temp control

[Chupidacabra]

So currently i use a cheap digital therm. It's a huuuuge pain. It takes a good minute to get to the actual temp and Iv recently noticed it might be a few degrees off.

Iv been thinking about a k type thermocouple(I have a probe rated for high temps and immersion from work). Anyone have an accurate cheap one?

An other option is a floating candy type? Any thoughts?

Thanks