Acidity and alkalinity are extremely important factors in your crop’s water and root zone. Ideal pH for your plants is 5.8-6.3. A pH reading out of that range indicates conditions that very much decrease your plants’ ability to take in hydroponics nutrients, grow well, and produce large harvests. Advanced Nutrients pH Down is a professional, pharmaceutical grade version of phosphoric acid that immediately lowers hydroponics pH without harming plants. So adjust pH as needed with our pure, safe ph Down.