Chemical dosing for the bor tevila
This tool does arithmetic on the numbers you type in. It does not know your water. Confirm every reading with a fresh test kit, and retest two to four hours after dosing.
Never mix chemicals with each other. Combining chlorine products, or chlorine with acid, releases toxic gas. Add chemicals to water, never water to chemicals. Dose with the circulation running and the mikvah empty of people. Follow your local health authority's rules for public bathing facilities, and your rav's guidance on treating the water of a bor tevila.
Testing this? Tell us what is wrong, what is missing, and what a real operator would not understand: