Pool Chemistry Calculator

You tested the water. Now what?

Pool Chemistry Calculator turns your test kit readings into an ordered plan: which product to add, how much of it, and in what order. Enter free chlorine, combined chlorine, pH, total alkalinity, calcium hardness, cyanuric acid and salt, and get amounts in the units your products actually come in — fluid ounces, quarts, pounds, grams, millilitres or litres.

Everything is calculated on your device. There is no account, no sign-up and no cloud.

DOSING THAT MATCHES YOUR POOL

• Volume wizard for rectangular, oval, round and kidney shapes, or enter a volume you already know
• Multiple pools and hot tubs, each with its own volume, surface, sanitizer and history
• Liquid chlorine, calcium hypochlorite, trichlor, dichlor and lithium hypochlorite, with adjustable product strength
• Sodium bicarbonate, soda ash, muriatic acid and dry acid for pH and alkalinity
• Calcium chloride, cyanuric acid and pool salt
• Every dose shows its side effects, so you can see the calcium that calcium hypochlorite adds and the stabiliser that trichlor adds before it becomes a problem
• Safety caps on every dose, with an ordered plan and wait steps between chemicals that should not be added together

A LOG, NOT JUST A CALCULATOR

• Save every test and build a season of history
• Filter by pool or hot tub
• Optional test reminders on the days and at the time you choose
• Your readings stay on your device

WATER BALANCE

• Saturation index calculator using pH, temperature, calcium hardness, alkalinity and total dissolved solids
• Alkalinity corrected for the cyanuric acid and borate that a test kit also picks up
• See which single adjustment moves your balance the most

CHLORINE AND STABILISER

• Chlorine target calculated from your cyanuric acid level instead of a fixed number, so a stabilised pool and a fresh fill are not treated the same
• Breakpoint target when combined chlorine is present
• Dilution estimates when cyanuric acid, calcium or salt are too high to correct with chemicals

GUIDES WRITTEN TO BE READ ONCE AND UNDERSTOOD

Cloudy water, green water, that strong chlorine smell, pH that will not stay put, salt generators, hot tubs, and how to handle pool chemicals without incident.

UNITS AND LANGUAGES

Full US and metric support. Gallons or litres, Fahrenheit or Celsius, pounds and ounces or kilograms and grams. Switch at any time — your saved history converts with you. Available in 50+ languages.

FREE, AND STAYING THAT WAY

There is no subscription and no in-app purchase. Nothing is locked. The app is paid for by advertising, and if the ads are in your way you can switch all of them off for five minutes by watching one short video, as often as you like.

IMPORTANT

This app performs calculations from the readings you enter. It does not test your water, it does not monitor your pool, and it does not tell you when your water is ready to use. Always follow the instructions on your chemical products, never mix chemicals, circulate the water after adding anything, and retest before use.

Recent changes:
First release: dosing plans from your test results, test history, water balance and practical guides.