255-214 & 255-215 Hook Gauges

The 255-214 (English) & 255-215 (Metric) Hook Gauge is used to measure water level changes inside an evaporation pan. NovaLynx produces a micrometer-style hook gauge that conforms to the traditional US Weather Bureau design. It features a sharply pointed, U-shaped hook that is attached to a calibrated stem with a micrometer dial. Measurements are taken by placing the gauge into an evaporation pan and onto a stilling well. The micrometer dial is then rotated until the tip of the hook pierces the water's surface from below. The hook's point is adjusted daily and the new dial reading is recorded to determine the amount of water loss.

Hook gauges are often used in conjunction with a 255-205 Stillwell for more accuracy.