The Hexeal Pool pH Minus helps you to keep your pool pH at the optimum level. The reason it is so important to maintain the correct pH is because if the pH is too high the effectiveness of all chlorine sanitisers starts to decrease. In addition to this water that is low in pH (acidic) can be corrosive to pool pumps, heat exchangers and damage the pool lining. We offer a solution to both of these problems. A pH imbalance can also contribute to skin and eye irritation, which you clearly want to avoid. We recommend that you always aim for a pH level of between 7.2 and 7.6. pH minus / reducer is suitable for use in swimming pools, spas or hot tubs. pH minus / reducer can be added directly to the pool water to reduce the pH to a desirable level.