BIONOVA - PH - PH REDUCER - 1000LBionova pH pH reducer Concentration 1: 3000 NPK 0 0 0 Phosphoric acid solution 24. 5%. This product is used to adjust the pH of a fertilizer solution downwards. Bionova pH is a phosphoric acid solution containing 24. 5%. It is crucial to manage pH values of the water nutrient solution you feed to the plant. Plants only absorb all nutrients when applied in the correct pH value. When your pH is to low or to high, the plant wont be able to uptake all