Dutch Pro pH Down Bloom reduces the pH level of the nutrient solution. The formula is perfect for use during the flowering stage because it provides a supply of Phosphorus. Growers can also use it in the vegetative phase but the better choice for the growth stage is Dutch Pro pH Down Grow (Nitric Acid). The formula is highly concentrated. The recommended pH level is between 5.5 and 6.5. Add small quantities of pH-Bloom to the nutrient solution until you reach the right pH level.