Floating Thermometer

A simple, reliable analog thermometer for your hot tub — and a handy second opinion on what the topside display claims. Use it sink-or-float: drop it to the bottom to read the water core, or use the float cap and let it ride the surface on its anchor cord.

Why bother when the spa has a sensor? The topside reads the temperature at one sensor in the plumbing — not necessarily what your body feels at the seats. An independent thermometer settles "it feels hotter than 102" debates, helps you dial in energy-saving setbacks, and is the first diagnostic when you suspect the sensor is drifting.

Size: 6-1/2" in sink mode, 8" with the float cap on. No batteries, nothing to calibrate — toss it in and read it.