Hanna Instruments

A Hanna checker takes the argument out of a test result. No card held up against a window, no two people reading the same vial two different ways. A number, repeatable, that you can chart against last week.

What is on this shelf: the single-parameter Checker HC colorimeters most reef tanks run on, handheld meters for alkalinity, calcium, phosphate, phosphorus and nitrate, pH and ORP testers and their electrodes, and the consumables that keep all of it working. Reagents, calibration buffer sachets, electrode storage solution, cuvettes.

The consumables are the part people underestimate. A checker is bought once; reagent is not. A pH electrode is a wear item that drifts and eventually stops holding calibration no matter how carefully it is stored. Buy the storage solution at the same time as the electrode, because an electrode left to dry out is a dead electrode.

Low-range and ultra-low-range versions of the same test are not interchangeable, and the reagents are not either. Check where your tank actually sits before ordering.