Hanna Saltwater Aquarium Alkalinity Colorimeter (dKH) Checker - HI-772

The Hanna HI772 measures marine alkalinity and displays the result in dKH, the unit commonly used when tracking carbonate hardness in reef aquariums. Its measuring range is 0.0–20.0 dKH, with results shown in 0.1 dKH increments.

A colorimetric test turns a prepared aquarium-water sample into a digital measurement. Use the correct sample volume and reagent amount, and follow the supplied procedure for zeroing and reading the cuvette. The Checker measures alkalinity rather than pH, so those two tests answer different questions about the aquarium.

Regular readings can help establish the system's alkalinity trend before adjustments to supplementation. Use the HI772 method and its specified replacement reagents consistently, and record results alongside maintenance or dosing changes.