HydroDynamics Ionic® Grow Hardwater is purposely blended to be more acidic than standard Ionic® Grow. Use this formula to facilitate vigorous plant growth in the vegetative or flowering plant stages. However, this formula is a more acidic nutrient solution that will neutralise bicarbonates on its own. Therefore it will reduce the amount of acid needed to control the pH in the reservoir and reduce the possibility of acute phosphate accumulation. It is also formulated to take into account the minerals, such as calcium, that are usually present in hard water. This is great for all grow areas with hard well or tap water! Quantity: 1 Gallon.