What is pH?

pH is a scale that measures the “potential” of “hydrogen” – the number of hydrogen ions in water.  The scale ranges from 1 – 14.  The lower the number, the more acidic the water is.  The higher the number, the more alkaline the water is.  A value of 7 is neutral.  Most freshwater fish prefer slightly acidic water to neutral water in a range from about 6 – 7.5. Decaying plants can lower the pH.  If pH drops below 5, bacteria levels decrease to a point that wastes cannot be broken down and most fish will not survive. pH can be measured using a simple inexpensive test kit readily available at Walmart.  The kits include drops that can be added to increase or decrease the pH level.  The drops are usually phosphate based and will encourage algae growth.  pH is difficult to lower in hard water.