pH-Down 1-5-0 is a Dyna-Gro product used to lower the pH of water.
What is pH?
Application Rates
Before adding the nutrient solution:
Using a pH meter to measure the acidity or alkalinity of the water. If the pH is higher than 6.5, add pH-Down to nutrient solution in ½ tsp. per gallon increments until desired pH is achieved.