NT Labs Aquarium Narrow pH Test. For fish with specific pH requirements or for general tropical community aquaria requiring a neutral pH, the pH 6–7.6 Test provides quick and accurate pH measurement. It also offers precision with 0.2 unit determination.
Ensure the test tube is clean.
Take a 5ml sample of water into the test tube.
Add 5 drops of the pH reagent; replace the test tube cap and shake thoroughly.
Compare the colour of your sample to the colour scale provided.