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Pool Chemistry Quick Reference

Reference Safety Updated Jul 24, 2026 ยท Pool Service

Overview

Quick-reference dosing + target chart for residential pool service. Carry this on every route - chemistry math under sun-and-time-pressure is where calculation errors happen. The right answer is on the card, not in your head.

Reference Table

Targets and effects, residential pool (per 10,000 gallons unless noted):

Parameter Target Effect of low Effect of high
Free Chlorine (FC) 1 - 3 ppm Bacteria, algae growth Bather discomfort, equipment corrosion
pH 7.4 - 7.6 Eye/skin irritation, corrosion Reduced chlorine effectiveness, scale
Total Alkalinity (TA) 80 - 120 ppm pH bounces wildly pH drifts up; cloudy water
Calcium Hardness (CH) 200 - 400 ppm Water aggressive on plaster/metal Scale on heater + tile
Cyanuric Acid (CYA) 30 - 50 ppm Chlorine burns off in sun Chlorine effectiveness reduced ("chlorine lock")
Salt (salt pools only) 2,700 - 3,400 ppm Cell underproduces chlorine Corrosion, cell shutdown

Dosing rules of thumb (per 10,000 gallons):

To raise By Add
FC 1 ppm 1.6 oz cal-hypo 65 % OR 11 oz liquid bleach 12.5 %
pH 0.2 8 oz soda ash (if TA low first, use sodium bicarb)
TA 10 ppm 24 oz sodium bicarbonate
CH 10 ppm 16 oz calcium chloride
CYA 10 ppm 13 oz stabilizer

To LOWER:

To lower By Add or do
pH 0.2 6 oz muriatic acid (31.45 %) OR 5 oz dry acid
TA 10 ppm Aeration + acid (slow process - 7 - 14 days)
CYA Any Only by partial drain + dilute (no chemical reduces CYA reliably)

Notes

  • Test pH BEFORE chlorine. High pH reduces chlorine's sanitizing effectiveness immediately; dosing chlorine without correcting pH wastes product.
  • TA buffers pH. Adjust TA first, then pH - adjusting pH with TA out of range causes pH to bounce back up within hours.
  • Cyanuric acid (stabilizer) protects chlorine from UV but at too-high levels causes "chlorine lock" - chlorine reads in the water but doesn't actively sanitize. Above 100 ppm CYA, the only fix is partial drain + dilute.
  • CYA accumulates because nothing breaks it down. Rain dilution helps but rarely enough; plan a partial drain every 2 - 3 years in stabilizer-heavy pools.
  • Salt pools need ZERO additional chlorine - the cell makes it from the salt. Constantly adding chlorine "to be safe" raises CYA (most stabilized tabs) and creates lock conditions.
  • Customer education shortcut: "Test once a week, adjust pH first, then chlorine. Most pools only need 1 - 2 chemicals per week."

NEVER mix chemicals - even at the truck. Pool acid + chlorine produces chlorine gas (a fatality risk). Store on opposite ends of the truck. Add EACH chemical to water (not water to chemical), one at a time, and walk away from the dosing area to let each disperse before adding the next.

References

  • NSPF / PHTA Certified Pool Operator (CPO) Manual
  • Taylor Technologies K-2006 Reference Guide
  • Manuall internal: Weekly Recurring Pool Service, Cloudy Pool Water - Diagnostic Tree

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