The pH factor (or potential Hydrogen) and hardness, are by far the most important chemical aspects of your Koi pond‘s water chemistry. These two factors have a large impact on the longevity of your Koi fish.

Understanding pH Levels In Your Koi Pond

The pH of water is measured on a scale of 1 to 14, where 7 indicates that the Koi pond water is ‘neutral’.  Readings below 7 indicate that the Koi water is acidic, and anything above 7 indicates that it is alkaline. The Koi fish can adjust to gradual changes of pH from 7 to about 8.5. In such pH levels, the Koi fish can still survive and led a healthy life.

Even though hardness of water and pH are unique measures, they respond to each other chemically. Thus, if the Koi pond water has buffers, the pH can increase. Pure/distilled water that has no hardness will have a pH of 7.

The Dangers Of  Unstable pH Levels In Your Koi Pond

One thing to note here is that neutral pH is unstable and the tendency is then to become acidic. If the Koi water has no buffers, the pH can drop to as low as 4.2. In such acidic waters, the Koi fish’s gills will get burnt and they will eventually die. If the pH in your Koi pond ever drops to very low levels, increase the pH slowly. To raise the pH level slowly, use dolomite, oyster shell gravel or coral gravel in nylon filter bags inside the filters. The flowing water will pass through it, raising the pH to 7 or 7.3 within 2 days. To ensure that the pH does not fluctuate due to a fluctuation in water hardness, include gravel in your filtration system. The gravel needs to be changed every 9-12 months.

If the water is devoid of buffers and the pH drops to 6 or less, nitrifying bacteria can’t survive. These bacteria are vital for the break down of toxic fish waste, nitrite and ammonia. If the pH is low, toxic ammonia changes to non-toxic ammonium. But if you increase the pH rapidly, ammonium can change back to ammonia quickly, causing Koi fish fatalities.

It is always important to keep Koi pond test kits handy, so that you can check the water quality regularly. If you want your Koi fish to live longer and be healthy, you will have to monitor the chemical levels in the Koi pond water.

Water that looks clean can still have toxins and you need to ensure that your Koi pond is non-toxic for your fish. Remember, the most toxic cancer-causing pollutants are colorless, odorless and tasteless! Your Koi fish don’t have a separate toilet unlike us humans and so, you need to keep their habitat clean and flushed.