This p H Decreaser from Clearwater is designed to help your p H levels in order & help reduce the amount of alkaline in your pool water & making swimming in your pool more comfortable & reduce the risk of itchy skin & sore eyes. The recommended p H levels are between 7.2 & 7.6. When the p H levels in your water start to reach 7.6 then you will need to use the p H treatment. The p H balance can be altered by leaves, bugs, dead skin. Plain & simple to use, just dissolve the correct amount in warm water & then add the solution to the pool water, as close to the inlet valve as possible to ensure that it disperses evenly & to the best effects. It is recommended that you test the water again after 8 hours & if necessary alter the p H levels again. All warnings & instructions must be adhered to, which are clearly labelled on the packaging.