Two factors can affect water’s ability to deliver dissolved nutrients to your plants: the level of mineral salts in the water, as measured by PPM; and the pH of the water. “Hard” water that contains a high mineral content will not dissolve nutrients as effectively as water with a lower mineral content, so you may need to filter your water if it is high in mineral content. The ideal pH level for water used in a hydroponic system is between 5.8 and 6.2 (slightly acidic). If your water doesn’t meet this level, chemicals can be used to adjust the pH into the ideal range.