The pH level of your nutrient solution can be checked in two ways.

LIOUID PH TEST KIT

This is a simple and inexpensive way to measure pH. A re-agent is added to a sample of the solution, which changes colour according to the pH level. This is then compared to a colour card to give the pH. Although this may seem a bit crude, many professional gardeners use this method, as pH meters can be delicate.

PH METER

A probe which is dipped into the solution gives a digital reading of the pH level.