Is DPD the same as OTO in a pool test kit?

DPD and OTO are different reagents used in pool test kits to measure the concentration of free chlorine or bromine in the water. While they both serve the same purpose, they work differently and may provide slightly different results. Here's an explanation of each:

DPD (N,N-diethyl-p-phenylenediamine)

- DPD is a reagent that reacts with free chlorine or bromine in pool water to form a pink or red color.

- The intensity of the color produced is proportional to the concentration of free chlorine or bromine in the water.

- DPD test kits typically come with a color chart or comparator block to help you match the color of the water sample to a corresponding chlorine or bromine concentration.

OTO (orthotolidine)

- OTO is another reagent that reacts with free chlorine or bromine in pool water, but it produces a yellow color.

- The intensity of the yellow color produced is proportional to the concentration of free chlorine or bromine in the water.

- OTO test kits also come with a color chart or comparator block to help you match the color of the water sample to a corresponding chlorine or bromine concentration.

In summary, DPD and OTO are different reagents used in pool test kits to measure free chlorine or bromine concentration. Both reagents provide accurate results, but they work differently and produce slightly different colors. It's important to follow the instructions provided with your specific test kit to ensure accurate readings and proper pool maintenance.