Enter your test readings once. Get a complete water-balance report and an ordered dosing plan with the exact amounts — not ten disconnected calculators.
CYA-corrected LSI & chlorineBy a working pool proFree · no signup
Dosing, order-of-operations, and target ranges come from a real recurring-route operation and the Pool Service Mastery curriculum — not scraped from a forum. Ranges follow CDC MAHC, PHTA, and Taylor guidance.
How we calculate (and why it's more accurate than most)
CYA-corrected water balance (LSI)
Most calculators feed your total alkalinity straight into the Langelier Saturation Index. But cyanuric acid (stabilizer) shows up in a TA test without actually buffering scale — so at 50 ppm CYA you're carrying ~13–15 ppm of "fake" alkalinity. We subtract the cyanurate portion (pH-dependent) to use true carbonate alkalinity, so your LSI isn't falsely optimistic. LSI = pH + TF + CHF + AF − 12.1, with AF = log10(TA − CYA·f(pH)).
CYA-scaled chlorine target
Free chlorine has to scale with CYA. A flat "1–3 ppm" is why "properly chlorinated" pools still go green. We target ~7.5% of your CYA as free chlorine (minimum ~5%), and compute shock/SLAM off CYA too.
Dose in the right order
We sequence the plan the way a tech actually works a pool — alkalinity → pH → calcium → CYA → chlorine — with re-test gates, because adjusting one parameter moves the others.
Honest about precision
Doses are starting estimates for your volume and chemical strength. Always add a bit less than the max, re-test, and confirm against the product label (concentrations vary by brand).
Educational tool — not a substitute for professional advice or a water test. Handle pool chemicals carefully.