The pool chemical calculator calculates exact dosing amounts for chlorine, pH adjusters, alkalinity, and CYA stabilizer based on your pool volume and current water test readings. Supports both US gallons (imperial) and liters (metric).
Pool Volume
Current Water Test Readings
Target: 1–3 ppm
Target: 7.2–7.8
Target: 80–120 ppm
Target: 30–50 ppm
Dosing Recommendations
How to Use the Pool Chemical Calculator
Proper pool chemical balance requires testing and adjusting four key parameters: free chlorine (sanitizer), pH (acid/base balance), total alkalinity (pH buffer), and CYA stabilizer (chlorine protector). Adjust in this order: alkalinity first, then pH, then chlorine, then CYA.
Step 1: Test Your Water First
Never add chemicals without testing. Use a test strip or liquid test kit to measure all four parameters. Test strips are fast but less precise; liquid test kits (DPD reagent) are more accurate. Test at least twice per week in summer and weekly in off-peak season. Always test in the morning before the sun affects chlorine readings.
Step 2: Adjust Alkalinity First
Total alkalinity should be fixed before pH because alkalinity controls pH stability. To raise alkalinity, use sodium bicarbonate (baking soda) — about 1.5 lbs per 10,000 gallons raises TA by 10 ppm. To lower alkalinity, use muriatic acid added slowly near a return jet with the pump running. Allow 24 hours between adjustments.
Step 3: pH Adjustment
Once alkalinity is in range, adjust pH. To raise pH, use sodium carbonate (pH Up/soda ash) — about 6 oz per 10,000 gallons raises pH by 0.2 units. To lower pH, use muriatic acid (hydrochloric acid) — about 10 oz per 10,000 gallons lowers pH by 0.2 units. Add pH-down chemicals slowly near a return jet.
Step 4: Chlorinate and Stabilize
With pH in range (7.4-7.6), chlorine works most effectively. Add liquid chlorine (sodium hypochlorite) or granular chlorine in the evening to prevent UV degradation. CYA stabilizer should be added directly to the skimmer basket, not dissolved first — it dissolves slowly over 1-2 days. Never add stabilizer at the same time as chlorine shock.
FAQ
How do I calculate how much chlorine to add to my pool?
To raise free chlorine by 1 ppm in a 10,000-gallon pool, add approximately 1.3 oz of liquid bleach (10% sodium hypochlorite) or 0.8 oz of granular calcium hypochlorite (65% strength). This calculator does the math automatically based on your pool volume and current vs. target chlorine level.
What should pool pH be?
Pool pH should be maintained between 7.2 and 7.8, with 7.4-7.6 being ideal. Low pH (below 7.2) causes eye and skin irritation and corrodes equipment. High pH (above 7.8) reduces chlorine effectiveness — at pH 8.0, chlorine is only about 20% effective compared to 60%+ at pH 7.4.
What is pool alkalinity and why does it matter?
Total alkalinity (TA) acts as a pH buffer, keeping pH stable. Target range is 80-120 ppm. Low alkalinity causes pH to bounce wildly ('pH drift'). High alkalinity makes pH resistant to adjustment and can cause cloudy water and scaling. Use sodium bicarbonate (baking soda) to raise alkalinity.
How do I calculate my pool volume?
This calculator includes a pool volume helper. For a rectangular pool: length × width × average depth × 7.48 = gallons. For a round pool: diameter² × 0.785 × average depth × 7.48 = gallons. A 15×30 ft rectangular pool with 5 ft average depth holds about 16,875 gallons.
What is CYA in pool water?
Cyanuric acid (CYA) is a chlorine stabilizer that protects chlorine from UV degradation. Without CYA, direct sunlight can destroy 90% of chlorine in 2 hours. Target CYA level is 30-50 ppm for outdoor pools. Too much CYA (above 100 ppm) can reduce chlorine effectiveness significantly — a condition sometimes called 'chlorine lock.'
Is this pool chemical calculator accurate?
This calculator uses standard industry formulas for chemical dosing based on pool volume and desired adjustments. Results are estimates — always test your water after adding chemicals and before swimming. Chemical strengths (concentration percentages) and pool conditions vary. Add chemicals gradually and re-test.