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Testing the pool water is the most important regular care task, for the health and enjoyment of your swimmers and the longevity of your pool.

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Ideal Range (ppm)

Total alkalinity, plastered pools

Every ​ month

80 - 120 ppm

Total alkalinity, ​ vinyl, painted or fiberglass pools

Every ​ month

125 - 150 ppm

pH level of water

Every other day

7.2 - 7.6

Free chlorine

Every other day

1 - 3 ppm

Stabilizer-conditioner (cyanuric acid)

Start and middle of season

Minimum 30 ppm with tabs; minimum 75 ppm with liquid

Shock treatment

Every 7 to 10 days

5 - 10 ppm

Water hardness


100 - 500 ppm

Drain and refill pool

5-7 years

  • Test with a clean and accurate kit and fresh agents (replace kit annually)
  • The best time to test is early evening
  • Circulate water before testing
  • Do not take a sample next to return inlets
  • For maximum chlorine effectiveness, run pump at night when pool is not being used
  • Take samples 18 inches below the surface
  • Hold clean test vials upside down and push down in water
  • Measure carefully; the lowest point of a sample must meet the fill-line on the test vial
  • Add reagent drops to test water while holding the reagent bottle straight upside down
  • Do not cover test vials with fingers
  • Read results against a white background
  • Pour test residue into the water after testing, to oxidize test reagents

Always follow instructions for each test