Free Pool Calculators

What to add, in order

1. 01Total alkalinity

   130 → 90

   1.2 galMuriatic acid (31.45%)

   • Acid lowers pH along with alkalinity. Lower alkalinity first, let it circulate, then re-test pH before the next step.
   • Pour it slowly into the deep end in front of a return with the pump running. Always add acid to water, never water to acid.

2. 02pH

   7.9 → 7.5

   Re-test before adding anything

   • The acid in the alkalinity step lowers pH as well, usually below 7.5, so don't add more acid yet. Re-test pH once it has circulated.
   • If pH ends up too low, aerate the water by pointing the returns up or running a water feature. That raises pH without bringing alkalinity back up. If it is still too high, use the muriatic acid calculator for the remaining drop.

3. 03Calcium hardness

   220 → 300

   14.7 lbCalcium chloride (77%)

   • Calcium chloride heats up as it dissolves. Pre-dissolve it in a bucket of pool water and add it slowly.

4. 04Cyanuric acid (stabilizer)

   30 → 40

   1.25 lbCyanuric acid (stabilizer)

   • Stabilizer dissolves slowly. Put it in a sock in front of a return or in the skimmer basket, and give it about a week before re-testing.

5. 05Free chlorine

   2 → 4

   38 fl ozLiquid chlorine (12.5%)

   • Adds nothing but chlorine and a little salt. It loses strength in the heat, so a jug that has sat in the sun may be weaker than its label.

Add about three quarters of the dose, let the pump circulate for an hour, and re-test before adding the rest. Never mix chemicals together, and always add chemicals to water rather than water to chemicals. Add each chemical separately and let it circulate before the next one.