Pool Free Chlorine to Cyanuric Acid (FC/CYA Ratio) & SLAM Shock Calculator

Balance pool Free Chlorine against Cyanuric Acid (CYA) stabilizer level.

Target Daily Maintenance Free Chlorine
5.75 ppm FC
Minimum Algae-Prevention Floor (7.5% CYA) 3.75 ppm FC
SLAM Shock Level (40% CYA) 20 ppm FC
12.5% Liquid Chlorine to Hit Target 72.22 fl oz
Inputs
ppm CYA
Measured Cyanuric Acid (CYA) stabilizer level in ppm.
ppm FC
Current measured Free Chlorine (FC) in ppm.
gallons
Pool water volume in US gallons.
Results & Graph
Target Daily Maintenance Free Chlorine
5.75 ppm FC
Minimum Algae-Prevention Floor (7.5% CYA)
3.75 ppm FC
SLAM Shock Level (40% CYA)
20 ppm FC
12.5% Liquid Chlorine to Hit Target
72.22 fl oz

Target Daily Maintenance Free Chlorine

Graph 1 • Cyanuric Acid Ppm Sensitivity Recalculates the domain equation across 50% to 150% of the primary input while holding other parameters constant.
0 ppm FC 4.7 ppm FC 9.3 ppm FC 50%: 2.88 ppm FC 2.9 50% 75%: 4.31 ppm FC 4.3 75% 100%: 5.75 ppm FC 5.8 100% 125%: 7.19 ppm FC 7.2 125% 150%: 8.63 ppm FC 8.6 150%
Graph 2 • Primary & Supporting Metric Comparison Compares the primary output alongside supporting domain benchmarks.
Target Daily Maintenance Free Chlorine 5.75 ppm FC Minimum Algae-Prevention Floor (7.5% CYA) 3.75 ppm FC SLAM Shock Level (40% CYA) 20 ppm FC 12.5% Liquid Chlorine to Hit Target 72.22 fl oz
Graph 3 • Exact Output Table & Units Displays each calculated output in its exact domain unit.
Target Daily Maintenance Free Chlorine5.75 ppm FCMinimum Algae-Prevention Floor (7.5% CYA)3.75 ppm FCSLAM Shock Level (40% CYA)20 ppm FC12.5% Liquid Chlorine to Hit Target72.22 fl oz
Summary: At 50 ppm CYA, never let FC drop below 3.8 ppm; maintain 5.8 ppm daily (add 72.2 fl oz of 12.5% chlorine) or raise to 20 ppm (2.71 gal) for SLAM shock.
Summary: At 50 ppm CYA, never let FC drop below 3.8 ppm; maintain 5.8 ppm daily (add 72.2 fl oz of 12.5% chlorine) or raise to 20 ppm (2.71 gal) for SLAM shock.
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Formula & Mathematical Methodology: Pool FC / CYA & Shock Formula

MinFC = 0.075 × CYA
TargetFC = 0.115 × CYA
SLAMShockFC = 0.40 × CYA
Min_FC = 0.075 × CYA; Target_FC = 0.115 × CYA; SLAM_Shock_FC = 0.40 × CYA
  • cyanuricAcidPpm: Cyanuric Acid Ppm (ppm CYA)
  • currentFreeChlorinePpm: Current Free Chlorine Ppm (ppm FC)
  • poolVolumeGallons: Pool Volume Gallons (gallons)

Rounding: Physical package counts round up where appropriate; continuous measurements round to 2 decimal places.

Worked Example: Practical Benchmark: Pool FC / CYA & Shock

Balance pool Free Chlorine against Cyanuric Acid (CYA) stabilizer level.

  1. Enter your project dimensions, machining speeds, or recipe weights.
  2. Compute the governing equation: Min_FC = 0.075 × CYA; Target_FC = 0.115 × CYA; SLAM_Shock_FC = 0.40 × CYA.
  3. Review the primary result, supporting dimensions, and 3 SVG visualizations.
Result: Computes Pool FC / CYA & Shock via Min_FC = 0.075 × CYA; Target_FC = 0.115 × CYA; SLAM_Shock_FC = 0.40 × CYA.

Frequently Asked Questions

How does the Pool Free Chlorine to Cyanuric Acid (FC/CYA Ratio) & SLAM Shock Calculator calculate results?

It evaluates Min_FC = 0.075 × CYA; Target_FC = 0.115 × CYA; SLAM_Shock_FC = 0.40 × CYA directly in your browser and plots three custom SVG visualizations.

Can I compare different material dimensions or batch sizes side by side?

Yes. Click "Compare (0/3)" in the results toolbar to pin up to 3 scenarios side by side.

Can I print a clean shop or kitchen reference sheet?

Yes. Click the Print button in the results toolbar for a distraction-free worksheet.

Construction & Home · Landscaping & Outdoor

Pool Free Chlorine to Cyanuric Acid (FC/CYA Ratio) & SLAM Shock Calculator: inputs, method, and how to read the result

Balance pool Free Chlorine against Cyanuric Acid (CYA) stabilizer level.

Choose inputs for the case you are checking

The defaults are illustrative. Replace them with values for your case and keep the units shown beside each field.

  • Cyanuric Acid Ppm: Measured Cyanuric Acid (CYA) stabilizer level in ppm.
  • Current Free Chlorine Ppm: Current measured Free Chlorine (FC) in ppm.
  • Pool Volume Gallons: Pool water volume in US gallons.

What the calculation includes

With the default values shown, Target Daily Maintenance Free Chlorine is 5.75 ppm FC. The calculation follows Pool FC / CYA & Shock Formula; the formula and variable definitions above show how the inputs combine.

One-input check: With the other defaults held constant, changing Cyanuric Acid Ppm from 50 ppm CYA to 55 ppm CYA changes Target Daily Maintenance Free Chlorine from 5.75 ppm FC to 6.33 ppm FC. This is a comparison inside the calculator's stated model, not a prediction.

Where to use caution

  • Uses standard North American & metric trade dimensions, Machinery’s Handbook formulas, and culinary weight ratios.
  • Verify local municipal building codes, tool manufacturer limits, and food-safety time/temperature tables before execution.

Scope: Trade, Shop & Culinary Science Reference Standard Check the assumptions and limitations against your situation before relying on the estimate.

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