6: I purchased DPD reagent with gray spots, is it normal?
A: DPD residual chlorine, total chlorine, ozone reagent kits supporting the reagents are tablets. Due to the differences in the
color of the DPD material, the color of the product may be white, light gray or pale pink. If the tablet is dark, sticky, do no
use it .
7:How often should the measurement be completed?
A: Because DPD residual chlorine, total chlorine, ozone reagents react with the oxidizing substances in the air, resulting in
color deepening. Therefore, we suggest to finish the testing within 5 minutes after the addition of the reagent.
8:What are the factors in the water that interfere with the measurement?
• Oxidizing agents: bromine, iodine, bromamine, iodine, ozone, hydrogen peroxide, chromate, manganese oxide.
• Reducing agent: nitrite etc..