I love my TF-100, and keep it along with the small blue box Taylor ph/cl test and my plastic sampling cup out in the pool house (unheated, uncooled, but shaded) or on the screened in porch closer to the hot tub.
In fact just today I ordered an additional Taylor ph/cl blue box test kit from Dave for the sole use (and convenience) of the hot tub for daily tests so that I can leave the other one and the TF-100 down by the pool.