Flex Commercial Solutions pH Up raises and maintains the pH levels for hydroponic systems, soil, and other grow media. Maintaining pH levels is especially important as nutrients tend to lower pH levels due to their acidic properties, leading to a low pH level that hinders a plant’s ability to uptake essential nutrients. It is recommended to check pH levels daily for optimal results. Ideal pH ranges are 5.5 to 5.8 for hydroponics and 6.2 to 6.3 for soils, potted plants, and sphagnum moss.