Enter what your test strip or kit says and this calculator lists what to add, in the order to add it, with amounts for the product you actually own. For a 15,000 gallon pool with free chlorine 2 ppm, pH 7.8, total alkalinity 70 ppm, calcium 250 ppm and CYA 30 ppm the plan is 4.2 lb of baking soda, then 14.1 fl oz of 31.45% muriatic acid, then 23 fl oz of 12.5% liquid chlorine. Leave a field blank and it is skipped.
How the plan is calculated
Every dose is the pool's volume times the change you want times the amount of product that moves one ppm:
Product = gallons ÷ 10,000 × ppm change × product per ppm per 10,000 gal
Per 10,000 gal, 1 ppm of free chlorine is 10.24 fl oz of 12.5% liquid chlorine. Raising alkalinity 10 ppm takes 1.40 lb of baking soda, and raising calcium 10 ppm takes 1.20 lb of 77% calcium chloride. The acid dose for pH is different: it depends on how much alkalinity and stabilizer buffer the water, so we use the carbonate model and your own TA and CYA, and the answer is "about". Pour a part, circulate and retest.
The order of the steps
The list runs total alkalinity, pH, calcium, stabilizer, salt, chlorine. Alkalinity comes first because it holds pH steady, and pH decides how much of your chlorine is active. The Indiana health department's guide puts chlorine first and the alkalinity steps after it. We follow that in one case: if free chlorine is under 1 ppm (3 ppm in a spa), the chlorine step is marked and moved to the top, because unsafe water cannot wait for a pH fix.
Free chlorine depends on CYA
A flat "1 to 3 ppm" is what many labels and the Hayward and CircuPool manuals print. PHTA quotes 2 to 4 ppm, and the CDC code asks 2 ppm when CYA is used. Trouble Free Pool and Orenda tie chlorine to stabilizer: minimum 7.5% of CYA, working target 11.5%. Stabilizer slows chlorine's kill rate, so at CYA 30 the plan uses a minimum of 2.25 ppm and a target of 3.5 ppm, and at CYA 60 the target is nearly 7. We follow the ratio and print the fixed numbers beside it; the table below the calculator shows both. Salt pools get a lower ratio because a generator makes chlorine all day.
Cyanuric acid, alkalinity and calcium ranges
Ideal bands come from PHTA and ANSI/APSP-11, with the CDC Model Aquatic Health Code as the acceptable limits. Total alkalinity is 80 to 100 ppm with liquid chlorine, cal-hypo or a salt cell, and 100 to 120 ppm with dichlor, trichlor or bromine; the limits are 60 to 180 ppm. Pool forums run lower, around 50 to 90 ppm, because cyanurate counts in the reading. CYA is 30 to 50 ppm for chlorine pools, the cell's own manual for salt pools (Hayward 60 to 80 ppm, Pentair 30 to 50 ppm), and a warning above 90 ppm, the CDC ceiling. Calcium is 200 to 400 ppm.
SLAM box
Turn on the SLAM switch for green, cloudy or algae water, or enter total chlorine so the calculator can work out combined chlorine (total minus free). Above 0.4 ppm combined chlorine the SLAM box appears on its own. At CYA 40 and FC 2 ppm the shock level is 16 ppm (40% of CYA), which is 14 ppm more, or 1.68 gal of 12.5% liquid chlorine in 15,000 gal. Hold it until combined chlorine is 0.5 ppm or lower, overnight loss is 1 ppm or less and the water is clear. Use liquid chlorine, because dichlor and trichlor add CYA. Above CYA 80 ppm the level is impractical: drain first.
Chart, log and app
The pool chemical chart below lists every target and what raises or lowers it. The printable test log has your target range under each column, so write down each test and dose and keep it by the pump. The results update as you type and everything stays on this device, so it works like an app on your phone without an install. It replaces a spreadsheet: the same formulas, with the arithmetic done.
The next question
After the plan, check saturation in the LSI calculator. For one chemical, go deeper with the pool shock calculator, pool alkalinity calculator, pool pH calculator or pool stabilizer calculator. If the gallons are a guess, use the pool volume calculator. All tools are listed in pool chemistry.