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Pool Volume & TypeDon't know? Use the shape calculator
Drives your CYA target and FC math
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Current Test ReadingsEnter readings from your test kit (Taylor K-2006 or equivalent). Leave blank if you haven't tested a lever yet.
Target depends on CYA
Above 0.5 triggers SLAM
Target 7.4-7.6
Target 80-120
200-275 plaster, 175-225 vinyl
30-50 chlorine, 60-80 SWG, 0 indoor
For LSI calculation
Affiliate Disclosure: This calculator is free. Some product links are Amazon affiliate links tagged ayerguides-20. Product links and pricing are for the US market.
How This Calculator Works
- FC target scales with CYA. Minimum FC = CYA ÷ 7.5. Target band = minimum up to 1.5×. A fixed 2-4 ppm FC target undershoots any pool with CYA above 30. This is the FC:CYA ratio from Trouble Free Pool; the book teaches it as the single most important pool-chemistry insight.
- SLAM mode uses a different FC target. SLAM (Shock, Level, and Maintain) pushes FC to a CYA-keyed shock value (CYA 70 → FC 28) and holds it until three exit tests pass: CC < 0.5, overnight FC loss < 1 ppm, water visibly clear. Drop pH to 7.2 first. At CYA 75+, drain 30-50% before starting SLAM because the FC target gets impractical.
- Chlorine dosing uses manufacturer strength. Liquid chlorine 10% = 13 fl oz per 10K gal per 1 ppm FC. 12.5% = 10.7 fl oz. 6% bleach = 22 fl oz. Cal-hypo 65% = 2.0 oz weight. Dichlor 56% = 2.4 oz weight. Trichlor 90% = 1.5 oz weight. Cal-hypo adds 0.8 ppm CH per 1 ppm FC. Dichlor adds 0.9 ppm CYA per 1 ppm FC. Trichlor adds 0.6 ppm CYA per 1 ppm FC.
- pH dosing. Muriatic acid 31.45%: 3 fl oz per 10K gal per 0.1 pH drop (range 2-4 oz depending on TA). Soda ash: 7 oz per 10K gal per 0.2 pH rise (range 6-8 oz). Maximum single soda ash dose: 4 lb per 10K gal (exceeding causes a soda ash cloud).
- TA dosing. Baking soda (sodium bicarb): 1.5 lb per 10K gal per 10 ppm TA rise. Arm & Hammer grocery bicarb is identical chemistry to pool-store alkalinity increaser at roughly 30% of the price. To lower TA: muriatic acid 1.6 pints (25.6 fl oz) per 10K gal per 10 ppm TA drop, then aerate to restore pH without re-raising TA (acid-and-aerate method, never aerate first).
- CH dosing. Calcium chloride 77% dihydrate (common retail): 1.6 lb per 10K gal per 10 ppm CH rise. 100% anhydrous: 1.25 lb per 10K gal per 10 ppm. To lower CH: dilution only (partial drain and refill). No chemical treatment works reliably.
- CYA dosing. Granular stabilizer: 13 oz per 10K gal per 10 ppm CYA rise. Sock method or pre-dissolve. Wait 48-72 hours for full dissolution before retest. To lower CYA: dilution only.
- Salt dosing (SWG pools). 83 lb pool salt per 10K gal per 1,000 ppm salt rise. Brand targets: Pentair 3,600 ppm; Hayward 3,200 ppm; Jandy 3,000 ppm. Always confirm against your model's installation manual. Wait 24 hours for full dissolution before retest.
- LSI water balance. Langelier Saturation Index = pH + TF + CHF + AF − 12.1. Target range −0.3 to +0.3. Above +0.3 = scaling; below −0.3 = aggressive. Uses industry-standard factor lookups for temperature, calcium hardness, and alkalinity.