What is KH?

KH, also known as Total Alkalinity or Carbonate Hardness is a measure of the buffering capacity of the water in your aquarium. The buffering capacity refers to how well the aquarium can resist changes in pH.

Why test for KH?

Established aquariums tend to acidify over time. This decrease in pH is due to the natural release of organic acids by the fish and the release of acidic substances by the beneficial bacteria in the aquarium and filters. The buffer in the aquarium counteracts this change by effectively ‘mopping up’ these acids preventing the natural drop in pH. If the aquarium was allowed to drop in pH the fish would become very sick. Aquariums with excessive algae can show large pH fluctuations on a daily basis. This change is prevented if there is a sufficient KH. It is important to regularly check and maintain the KH as it will eventually run out.