Check the listing for details. Dyna Gro pH Down 32 oz. Quart 1-5-0 Nutritional Supplement for Plants. Condition: New. Listed at 22.99 USD. pH-Down 1-5-0 is a Dyna-Gro product used to lower the pH of water.What is pH?pH is a measure of acidity or alkalinity.For growing in soil, the pH range should be 6.0 to 6.5.In hydroponics, pH should be maintained between 5.5 and 6.0When the proper pH is achieved, the nutrients become more available to the plant. pH levels that are too low or too high can result in the release of, or tying up of minerals in soils that can lead to toxic or deficient levels of some mineral elements. If pH is too high, lower the pH using Dyna-Gro® pH-DOWN.pH of 7.0 is considered neutral.A lower pH is considered acidic and a higher pH is considered alkaline.Application RatesBefore 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.