pH is a term we come across quite often when discussing water quality. pH is the measure of the hydrogen ion concentration. The pH scale is graduated from 1 to 14. A value less than 7 indicates that the solution is acidic while a value greater than 7 indicates that the solution is alkaline.
The lesser the value of the pH, the more acidic the solution is. Thus a ph of 4.5 is more acidic than a pH of 5.
The pH scale is a logarithmic scale which means that a water of pH 5 is 10 times more acidic than a water of pH 6
Fish are very sensitive to pH. Fish which come from rivers such as guppies and mollies are comfortable at a higher pH or a less acidic aquarium water. On the other hand, fish such as cichlids which come from the African lakes require a lower pH and a more acidic water.
Hence, when having a community tank, you must keep in mind the different pH requirement of the fish. Mixing fish with different pH requirement such as angelfish and cichlids is not a good idea.
pH can be tested with pH test strips or test kits available at your pet store. You can also buy them online. Hand held meters are also available.
pH can be adjusted by doing partial water changes. Partial Water Changes slightly increase the pH.
Adding shells or crushed coral as a substrate can also increase the pH as these materials contain calcium carbonate.