What Is the Meaning of the pH Balance in Aquariums?

The quality of the water in your fish tank is crucial to the well-being of your fish.

The quality of the water in your fish tank is crucial to the well-being of your fish.

Becoming a fish keeper requires more than choosing a handful of swimmers at the store and tossing them in a bowl of tap water at home. You have to prepare the water before you bring fish home. Among the conditions you'll oversee is pH, a measure of hydrogen ion activity.

pH Basics

pH is actually a formula set by international standard. It is the decimal logarithm of the reciprocal of the hydrogen ion activity in a solution. The values produced represent a measure of a water sample's acidity or alkalinity. Water pH is measured on a scale of 0 to 14. Neutral or basic water measures 7 on the scale. A pH of 7 means that the water is perfectly balanced, neither alkaline or acidic. A pH lower than 7 means the water is acidic. A pH between 7 and 14 means the water is alkaline. "Balancing pH" refers to making sure your water is not too acidic or too alkaline for your fish.

Acidic and Alkaline

Aquarium water typically becomes acidic due to the activities of the fish within the aquarium. Fish fecal matter is mildly acidic and can build up over time, causing the pH to become more acidic. In some cases, your tap water may be acidic to start with, meaning that - for water - it has high acid levels. When water becomes alkaline, it normally does so because of calcium and magnesium in the water or being released from corals, shells or gravel within the tank.

pH Levels

A problem with your filter, overfeeding, too many fish in the tank or improper aquarium maintenance can cause your water to become too acidic for the fish to survive in long term. On the other hand, water that is not acidic enough can cause some fish to become stressed, sicked or even die. Fish have natural pH preferences in the wild, and you must be sure each of your fish can handle the pH of your tank. Placing a fish in a tank that has a drastically different pH than what the species is used to can cause serious health problems for the fish.

Adjusting pH

Test your aquarium's pH regularly and adjust as necessary, using products designed for testing and manipulating the pH in an aquarium. Make sure to research the type of fish you own and tailor the pH of your tank to meet the ideal conditions for the fish you plan on keeping in the tank. Check your pH every couple of days to avoid problems and catch any problems that may be developing early on.


About the Author

Jen Davis has been writing since 2004. She has served as a newspaper reporter and her freelance articles have appeared in magazines such as "Horses Incorporated," "The Paisley Pony" and "Alabama Living." Davis earned her Bachelor of Arts in communication with a concentration in journalism from Berry College in Rome, Ga.

Photo Credits

  • Ablestock.com/AbleStock.com/Getty Images