Personally, I like using an "HVAC" thermometer for taking water temps. I got my first one, from a heating and cooling contractor, my second one, I had to buy for around $16.00.
I like these thermos, over all the others I've used over the years, because they're all stainless, have an impact resistant glass face, (actually, hi-impact clear plastic), are quick to register the temp and because they're a "dial face" type thermometer, they are really easy to read, while still in the water.
I recently tried "something new", with my thermometer and that was to tie-wrap it, onto the lower 2 feet of my Falstaf wading stick. Works great!!
One more thing, about these certain units........... they're adjustable for perfect calibration!
I've broken way too many mercury style units, over the years and I don't like dropping mercury into my trout streams, no matter HOW small the dosage may be!!?!