Pentair OTO #2 Test Solution

OTO #2 is the reagent used to read chlorine and bromine in pool and spa water. This is the Pentair solution, listed under part numbers R161004 and R161007.

Why test

Sanitizer is the one number that does not hold still. It burns off in sun, gets used up by swimmers and rain, and a pool that read fine last week can be short by the weekend. Testing on a schedule is what tells you to dose before the water turns, rather than after.

Before you order

This is the reagent bottle alone, not a complete test kit, so it suits topping up a kit you already own. Note that the size for this item is published two ways, as 2 oz and as 1/2 oz. Both figures appear in the source data, so confirm the size against what your kit takes.