Pool chemical calculator

Enter your pool's size, your test results and the levels you want, and get each chemical to add, in order, with gauges showing where every level is now and where it ends up.

Inputs

Not sure? Work it out with the pool volume calculator.

ppm

Test with a DPD or FAS-DPD kit.

ppm

It depends on your stabilizer: about 7.5% of it at the least. The shock calculator has the chart.

7.4–7.6 is ideal; 7.2–7.8 is acceptable.

ppm
ppm

80–120 ppm is ideal.

ppm
ppm

200–400 ppm for a plaster or vinyl pool.

ppm
ppm

30–50 ppm is usual with liquid chlorine.

First to add: liquid chlorine

46.1fl oz

5 steps for 15,000 gal. Do them in this order, one at a time.

Split the muriatic acid into 2 doses, retesting between them. The Tulsa and Indiana guides cap a single dose (a pint of acid per 10,000 gal; 50 ppm of alkalinity). Add one chemical at a time, in the order shown.

1. Liquid chlorine
46.1 fl oz
2. Baking soda
6.43 lb
3. Muriatic acid
40.5 fl oz in 2 doses
4. Calcium chloride
12.6 lb
5. Stabilizer
1.25 lb
Pool levels before and after
Free chlorine2.0 → 5.0 ppm0.016.0Alkalinity70 → 90 ppm0240pH7.9 → 7.5 6.68.4Hardness180 → 250 ppm0600Stabilizer30 → 40 ppm0150NowAfter dosing

To bring 15,000 gal to your goals: 1. liquid chlorine: 46.1 fl oz; 2. baking soda: 6.43 lb; 3. muriatic acid: 40.5 fl oz in 2 doses; 4. calcium chloride: 12.6 lb; 5. stabilizer: 1.25 lb. After that the meters read free chlorine 5.0, alkalinity 90, pH 7.5, hardness 250, stabilizer 40. Each meter shows the level now (hollow marker) and after dosing (solid marker) against the usual range.

Add chemicals safely

Pool chemicals are hazardous. The doses below are estimates; the label and your test results decide what you actually add.

  • Follow the label on every product, for dose, handling and storage.
  • Add one chemical at a time, with the pump running, in the order shown. Let each one circulate and retest before you add the next. Indiana and Tulsa both give an order of application, and Tulsa says not to add large amounts at once.
  • Never mix chemicals with each other, in a bucket or in the pool. Chlorine products and acids give off dangerous gas if they meet. Use a clean scoop for each chemical and store them apart.
  • Add acid to water, never water to acid. Indiana’s rule is “Always Add Acid”.
  • Dissolve powders and crystals in a bucket of water before adding, and never put chemicals in the skimmer.
  • Keep swimmers out while you dose, and wear eye protection and gloves.

How it works

Every chemical has a known amount of the thing you want in it, so each dose is the change you want times the water volume times that amount:

dose = change × pool volume (L) × factor
chlorine:   grams of available chlorine = ppm × litres ÷ 1,000, divided by the product’s strength
alkalinity: 1 ppm as CaCO₃ = 1/50.04 meq/L;  baking soda 84.0 g per equivalent, acid 36.5 g of HCl per equivalent
hardness:   1 ppm as CaCO₃ = 1/100.09 mmol of calcium;  calcium chloride 111 g per mole
pH:         the published dose for a 0.2 change, scaled
  • Alkalinity and hardness are measured as calcium carbonate, and the amounts come straight from molar masses. They match the Taylor tables in the Tulsa manual and the Indiana table to within 1–3%.
  • Chlorine uses the strength you pick. Liquid products are read as grams of chlorine per 100 mL, which is how Taylor’s 10% = 12.8 fl oz per ppm in 10,000 gallons works out.
  • pH is the hardest to predict, so its doses are the published 0.2 steps (Yakima County, corroborated by Swim University). Acid and soda ash also shift alkalinity a little, about 5 ppm per 0.2, and the plan adjusts the baking soda for it.
  • Dichlor adds stabilizer and calcium hypochlorite adds hardness. The calculator subtracts what they bring, so you do not double up.
  • The meters show the level now (hollow marker) and after dosing (solid marker). Green is the usual range. For free chlorine it follows your stabilizer, at least 7.5% of CYA, rather than a flat 1–3 ppm.

Worked example

A 15,000 gallon pool, with the defaults: free chlorine 2 → 5, pH 7.9 → 7.5, alkalinity 70 → 90, calcium hardness 180 → 250 and stabilizer 30 → 40, using liquid chlorine:

  1. Liquid chlorine, 12.5%: 3 ppm × 56,781 L ÷ 1,000 ÷ 0.125 = 1,363 mL = 46 fl oz.
  2. Baking soda: alkalinity up 20 ppm, plus the 10.6 ppm the acid in step 3 will take out, is 30.6 ppm × 56,781 × 1.679 mg = 2,917 g = 6.4 lb, added in 1 dose (under 50 ppm).
  3. Muriatic acid, 31.45%: 0.4 of pH is two steps of 0.2 at 13.5 fl oz per 10,000 gal, scaled to 15,000 gal = 40.5 fl oz, split into 2 doses.
  4. Calcium chloride, 77%: 70 ppm × 56,781 × 1.44 mg = 5,724 g = 12.6 lb, on another day from the baking soda.
  5. Stabilizer: 10 ppm × 56,781 = 568 g = 1.25 lb.

Tips from the pool pad

  • Fix alkalinity before pH. If alkalinity is off, every pH correction drifts back. The calculator puts alkalinity first for that reason.
  • Wait and retest. Give each chemical time to circulate, and never chase a number with a second dose before you have tested.
  • Dissolved stabilizer takes days. Cyanuric acid dissolves slowly; keep the pump running and do not backwash for a few days or you will pull it into the filter.
  • Your real volume matters. A 10% error in gallons is a 10% error in every dose. The pool volume calculator will give you a better number than a guess.

FAQ

In what order should I add pool chemicals?

Chlorine first, then total alkalinity, then pH, then calcium hardness, then stabilizer. That is the Tulsa guide's order; the Indiana guide puts stabilizer before hardness. Adjust alkalinity before pH because alkalinity buffers pH, and do not add calcium chloride on the same day as baking soda.

How much baking soda raises alkalinity?

About 1.4 lb per 10,000 gallons for each 10 ppm. The Taylor table in the Tulsa manual and the Indiana guide both say 1.40 lb; Swim University and some retailers round it to 1.5 lb. In metric, 1.68 g per 1,000 litres raises alkalinity by 1 ppm. Raise it by no more than about 50 ppm at a time.

Why does the pH dose look so rough?

Because pH depends on how strongly the water is buffered, and no table can see your water. The figures here are the published doses for a 0.2 change per 10,000 gallons: 6 oz of soda ash up, or about 13.5 fl oz of 31.45% muriatic acid down. Sources disagree by a factor of two or more, so treat it as a first dose, retest after an hour of circulation and repeat.

Why is my acid split into several doses?

The Tulsa manual says never to add more than one pint of muriatic acid per 10,000 gallons at once (the Indiana guide says a quart). The calculator uses the stricter limit and tells you how many doses to split it into, with a retest between each.

What if a level is already too high?

Free chlorine falls by itself. Alkalinity comes down with acid, and the calculator works that out. Calcium hardness and stabilizer cannot be lowered with a chemical; the only way is to replace water. The calculator gives the share of the pool to drain and refill, assuming the fresh water has none.

Sources

  1. Pool Operators Permit Instruction Manual (section 5 dosage tables, reprinted from Taylor Technologies), Tulsa Health Department. Tables A–J per 10,000 gal, e.g. baking soda 1.40 lb per 10 ppm of alkalinity, calcium chloride (77%) 1.20 lb per 10 ppm of hardness, muriatic acid (31.45%) 1.60 pints per 10 ppm of alkalinity. Order of application; the chemical standards (pH 7.4–7.6, alkalinity 80–120); chemical safety rules.
  2. Adjusting Chemical Levels in a Swimming Pool (Water Chemistry Adjustment Guide), Indiana Department of Health (adapted from the NSPF Pool & Spa Operator Handbook). Dosages per 10,000 gal for chlorine, alkalinity, hardness and stabilizer (baking soda 1.4 lb per 10 ppm; 13 oz of cyanuric acid per 10 ppm); no more than about 50 ppm of alkalinity at a time; add acid to water.
  3. Dosages Required To Chemically Treat 10,000 Gallons Of Water, Yakima County, Washington, Environmental Health. Soda ash 6 oz raises pH by 0.2 (and alkalinity by about 5 ppm); 35% muriatic acid 12 fl oz or dry acid 1 lb lowers pH by 0.2 (and alkalinity by about 5 ppm). "Amounts may vary depending on initial pH levels."
  4. PoolMath worked example, Trouble Free Pool. Read from a Wayback Machine copy, because the site itself blocks automated access. A 14,900 gal pool from FC 0, TA 60, CH 30, CYA 0 to FC 6, TA 80, CH 60, CYA 40 takes 185 oz of 6% bleach, 70 oz of baking soda, 88 oz of calcium chloride dihydrate and 80 oz of stabilizer.
  5. How Much of Each Chemical to Add to Your Pool, Swim University. 1.5 lb of alkalinity increaser per 10,000 gal for 10 ppm; 6–8 oz of soda ash per 10,000 gal to raise pH by 0.2.

Formula and sources last checked September 30, 2026. How we test formulas.

  • Pool shock calculatorHow much liquid chlorine, bleach, cal-hypo or dichlor shocks your pool, with the shock (SLAM) level for your cyanuric acid and a free chlorine vs CYA chart.
  • Pool salt calculatorHow many pounds of salt and how many bags take your saltwater pool from its current ppm to the level your chlorine generator wants, with a ppm meter and bags.
  • Pool volume calculatorHow many gallons is your pool? Rectangle, round, oval, oblong or kidney, with a flat or sloped floor, drawn from above and from the side.
  • Hot tub chemical calculatorHow much dichlor or chlorine, baking soda, pH down and calcium to balance your hot tub by its size, in order, with before and after meters for spa ranges.
  • Hot tub volume calculatorEstimate how many gallons your hot tub or spa holds from its size, for portable acrylic spas, wooden and in-ground tubs, and inflatables.
  • Pond liner size & volume calculatorWhat size pond liner you need and how many gallons your pond holds, for rectangular, round, oval and free-form ponds, drawn on the liner.

Safety note: Estimates only. Equipment ratings vary by manufacturer, so always follow the manufacturer’s instructions and ratings, and ask a qualified professional when safety is at stake.