PH DOWN 500 ML FOR HYDROPONIC NUTRIENT Each Pack Contain pH Down 500 ml INSTRUCTIONS: Use sparingly - add to nutrient solution, a little at a time, then test pH. Repeat application, then test, until desired pH is achieved. The quantity necessary for pH adjustment will vary depending on the strength of the nutrient and the purity of the water used to mix nutrient. This product lowers nutrient pH. Recommended pH for most plants is 5.5 to 6.5. CAUTION Use only to lower the pH of nutrient solution and plant fertilizers.