What You Need to Know About pH in Your Aquaponics Fish Tank

What You Need to Know About pH in Your Aquaponics Fish Tank

In chemistry, pH  is a number used to describe the acidity or alkalinity of water.  It is calculated by measuring the activity of hydrogen ions.  If you are a chemist and know what logarithms are, you can use this formula to calculate the pH of the water in your fish tank:

pH formula

If you didn’t take chemistry in high school and have misplaced your slide rule, there are test kits you can buy at most pets stores or on Amazon.

The pH of water can be less that 0 (very acidic) or up to and above 14 (very akaline).  You would not want to drink water that had a pH of 0 or 14 and your fish would not survive such extreme conditions.  Pure water would have a pH of 7.  When I tested the tap water in my home, I got a reading of 8.0.

Fortunately, freshwater fish can tolerate a rather wide range of pH that is not difficult to control.  I keep koi and goldfish in my tanks and they are doing well with 8.0 pH.  If you keep your tanks at a pH between 6.5 to 8.5, your fish should be fine.  Although fish can tolerate and survive in water out of that range, they may not do as well.

It is important to know and control the pH of your fish tanks but don’t be too concerned if the pH changes over time so long as it is in the recommended range.  If the pH does move outside the recommended range, there are several products available is pet stores that will raise or lower it.  Use caution, however, and do not change the pH too rapidly or your fish may become stressed.

One of the best resources that I have found for complete information about aquaponics is ASC Magazine.

Photo by ThatWikiGuy

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