Information When Dipping and Waiting: Don't dip the strip for too long time. 2 seconds is enough.Don't stir the strip in water.Don't shake, wipe or dry test strip. Each absorbent pad on the strip is specially treated with a chemical that reacts with pool chemicals and causes the color changing. Above actions take away and mix the chemicals on the pads and make the results inaccurate.When Matching Colors: If you use Chlorine to sanitize the pool, please check all 6 measurements on the strip.If you use Bromine to sanitize the pool, you will only need to check 4 measurements: Bromine, pH, Total Alkalinity, and Total Hardness. Chlorine free pool doesn't need stabilizer (Cyanuaric Acid), so the Total Chlorine and Cyanuaric Acid pads colors won't match.If you use salt Chlorine generator (salt water pool), you will need to check 7 measurements: Salt, Free Chlorine, Cyanuric Acid, Total Alkalinity, Total Hardness, pH, Total Dissolved Solids (TDS). Our test strip doesn't test for Salt and TDS. Salt Test Strip is sold separately and TDS is not often tested unless pool water conditions have become unmanageable. Don't touch the pads. Match Colors within 3 minutes. Colors fade after a few minutes. Don't wait too long. Every time before jumping into the pool, use test strips to check your pool water and make sure it is chemical balanced and safe for your health.Regular pool water testing and maintenance of the chemicals are essential for ensuring a safe, comfortable swimming environment and preserving the longevity of pool finishes and equipment.50 strips mean 50 tests. Test strip is cost-effective and reasonably accurate, compared to expensive test kits or pool service. Tests for 7 Most Critical Parameters Total ChlorineFree Chlorine/Bromine - the second segment can test two parameters.pHTotal HardnessTotal AlkalinityCyanuric Acid The ideal range for each parameter are marked on the bottle, helping you to know if the water is chemical balanced for your health. Add the appropriate pool chemicals as necessary to keep the parameters in the ideal ranges.