Exact doses for your gallons — chlorine, acid, baking soda, stabilizer, salt — plus a guided rescue when the water's gone green. Doses round down on purpose.
Pick what you're adjusting — chlorine, pH, total alkalinity, cyanuric acid (stabilizer), or salt — enter your pool's volume in gallons and your current test reading, and you'll get the exact amount to add for your water, not a generic chart figure. Don't know your gallons? For a rectangular pool, multiply length × width × average depth (in feet) × 7.5. A rough number is fine for dosing.
Overshooting a chemical correction is harder to undo than undershooting it — too much acid can crash your pH, too much chlorine means waiting to swim. Every dose here rounds down, and large corrections split into "add about two-thirds, circulate, retest, then finish." One extra test, far less risk of a chemistry swing you have to reverse.
A green pool is almost always an algae bloom from low or interrupted chlorine. The fix is order-dependent: net out debris and brush the walls and floor, correct pH first if it's above 7.8 (chlorine works poorly at high pH), then shock with chlorine sized to your volume and how green the water is, running the filter 24/7 and retesting every 12–24 hours. Green Pool Rescue mode above gives you the exact initial shock, a shopping list sized for the whole cleanup, and the full step order. For the rigorous enthusiast method, Trouble Free Pool's SLAM process is the gold standard; this is the simplified guided version.
These are estimates from standard pool dosing chemistry — always follow the product label, and never mix chlorine and acid or add them at the same time. pH and alkalinity especially interact, so the calculator leans conservative and asks you to retest before re-dosing. When in doubt, add less and test again.
It depends on your gallons and how far your free chlorine is below target. For 12.5% liquid chlorine, about 10 fl oz raises 10,000 gallons by 1 ppm — enter your numbers above for the exact amount.
Acid demand scales with your volume, current pH, and total alkalinity. Large drops should be split — add about two-thirds, circulate, retest, then finish. Use Lower pH mode for a specific amount.
Rectangular: length × width × average depth (ft) × 7.5. Round: diameter² × average depth × 5.9. A rough figure is fine for chemical dosing.