Growth Technology pH Up is a 480 grams/litre solution of potassium hydroxide (KOH) and is very alkaline. It should be handled with extreme care. This is used mainly by growers who use reverse osmosis water (or rainwater) which have very low pH buffering capacity and the acidic nature of hydroponic nutrients tends to make a nutrient solution with a lower than desired pH. Hence the need to use pH Up.
