pH up and pH down are tank controllers that will adjust your solution to the desired pH.
pH is a measure of the acidity or alkalinity of a solution. The pH scale ranges from 1 to 14.
pH 7.0 is considered neutral and is based on pure water.
Solutions with a pH less than 7 are considered acidic, while those above 7 are considered basic (alkaline). pH effects nutrient uptake for most plants. The optimum pH range for plants is from 5.8 to 6.5.
pH up and down comes in both concentrated and ready to use (RTU) forms.