TERPINATOR® has a neutral PH of about 6 and should not affect your parts per millions (PPMs). This product can be used from vegetating state all the way through flush. We recommend 15 - 30 ml/Gal for the last 4-6 weeks of flowers, and all the way through flush. TERPINATOR® has been tested at a very high concentrations with a large variety of nutrients and mediums - never with any results of burning or negative effects. Therefore, it can be used through the entire cycle of growth without concern.