The key to successful fish keeping is excellent water quality. The Pond Lab Mini-Tests measures three water parameters: pH, Nitrite and Ammonia.
Detailed pictorial instructions are included on the back/sides of the box. Simply follow the instructions and then compare the colour in the test tubes to the colour guide on the back/sides of the box. A full instruction leaflet is included in the pack which talks you through each parameter, what it should be, and what you should do if the readings are incorrect.