Description

LaMotte 3919-E is a biguanide test solution supplied as a 15 mL liquid reagent. It measures the biguanide sanitizer level in pool and spa water.

How it is used

The reagent is added to a measured water sample and reacts to produce a color change. Reading that color against the scale gives the sanitizer concentration, which is the number a biguanide pool has to be run by.

Why routine testing matters on biguanide

Biguanide is not chlorine and it does not behave like chlorine. The sanitizer has to be held in its own range, and the only way to know where it sits is to test it on a schedule. Reagents also age: heat and sunlight take the accuracy out of a bottle, so keep it capped, stored cool, and replace it rather than pushing an old bottle through another season.