To maximize plant growth, the pH level of your nutrients should be slightly acidic. Experienced growers consider the ideal pH for most crops to fall between 5.5 and 6.5. While almost all Midwest products are pH balanced, there are some conditions which require adjusting: tapwater quality changes, pH unstable growing media, or unusually high growth rates can also destabilize pH.
pH Down is formulated with food-grade Phosphoric acid. Just add a little at a time if your nutrient pH is too high in order to lower the pH to the proper level.
Always use a pH test to accurately determine your additions. We suggest a RAPITEST SOIL PH TEST KIT
or a CHECKER 1 ECONOMICAL PH TESTER