Advanced Nutrients®, pH Down, Water pH Adjuster (10 Liter)Advanced Nutrients pH Down, Water pH Adjuster (10 Liter) Say goodbye to nutrient lockout and hello to heavier harvests. Our scientists engineered pH Up with potassium hydroxide and pH Down with Phosphoric Acid, so you can easily achieve the ideal pH levels for optimal nutrient absorption. Weve developed these highly stable buffers to give you precise control over your pH, even after dilution or adjustments between reservoir changes. Recalibrate pH