PPM 500 (TDS)

or RO water (will damage probe sensitivity)

The Milwaukee MW11 Total Chlorine Photometer lets you go digital with your testing

MW605 meter

✅ 100 gallons or 90 days per filter — lasts up to 2× longer than common pitcher filters

Hanna Free and Total Chlorine CAL Check Standards - HI93414-11 858502005111 PPM 500 (TDS)The HI93414 11 Free and Total Chlorine CAL Check Standards provide a simple solution to calibrating and validating compatible benchtop and portable photometers. This high quality set of standards is manufactured in our state of the art facility and comes supplied with a certificate of analysis. The certificate of analysis provides the lot number, reference values, and expiration date for traceability when certifying compatible free and total chlorine