Simply dip the testing strip into the water which is to be tested for a few seconds.
Remove the strip from the water and compare to the colour chart on the bottle to determine the pH value of the water.
Different fish have different pH requirements.
Once you have determined the pH requirements of your specific fish, gradually adjust the pH in the aquarium or pond to the correct value by adding a natural pH buffer or by using a pH up or pH down fluid or powder.
Do not make large adjustments within a 24 hour period.
Test the pH once a week as it may have changed.