Mills Nutrients Basis A & B for Hard Water work together to give your plants the ability to absorb all of the essential vitamins and minerals they need to grow quickly, flower heavy, boost the immune response and overall crop better. It can be used right across the lifecycle of your plants, from young seedlings to blossoming plants, giving them the food they need to thrive. A & B together will deliver the calcium, red iron, magnesium and a wealth of other minerals and nutrients to boost cell growth, provide enhanced absorption, and give a superior end result. Available in 4 sizes. No plant growth regulators guaranteed.