The Basic Nitrogen Cycle
Water Quality - Ph - Ammonia - Nitrites - Nitrates - Oxygen Levels
Filter Filter Filter: Filtration is one of the most important aspects of keeping your koi healthy. You can never have to much filtration. Calculate the volume of your pond and make sure that your pump can handle at the minimum, of turning over the complete volume of your pond every 2 hours, 1 hour is even better. If you need multiple systems then the investment is well worth it. Remember that they are living in there own toilet bowl and us humans need to regulate that water so that it is as free of waste and detrius as possible at all times.
Water Quality : When you appreciate that water is to koi fish like air is to humans, you begin to appreciate why water quality is so important to koi. To illustrate: imagine you had a very slight gas leak in your house. You can't see the gas and you don't recognize the smell, but you find that after a few weeks you don't feel well. The gas itself is not bad enough to kill you, but your resistance is lowered, because your body has to constantly work to repair the damage the gas is causing. In time you find that you get sick easily, whether it is a cold, the flu or whatever you are exposed to. On the other hand, if the gas leak suddenly got bad enough, it alone could kill you. It is very similar with fish and pond water. Poor water quality will kill your fish faster than anything else. Low oxygen in a pond can kill every fish in the pond overnight. High ammonia levels can kill fish within several days. But, even marginal levels of oxygen, ammonia and nitrates can set your fish up to fall victim to other life threatening problems. So, the goal should always be to have the best water quality possible. There are basically five water quality items you need to be concerned with, ph, ammonia, nitrite, nitrate and oxygen.
Ph is a measurement of whether the water is acidic of alkaline. Ph is measured on a scale ranging from 1 to 14 with 7.0 being neutral. Any measurement below 7.0 is considered acidic and any measurement above 7.0 is alkaline. The ideal ph for koi fish is 7.4 but koi will do quite well in water ranging from 7.0 to 9.0 as long as it does not fluctuate too much. Imagine you have a concrete pond that normally has a ph of 8.5 and you are constantly adding acid to the pond to lower the ph to 7.4. If each week the Ph bounces back up toward 8.5 again, you are doing much more harm to your koi than any possible good that might be gained by getting the ph to stay at 7.4. Koi fish do not do well with constant change so leave it alone. What you do need to watch for is a "ph crash". A "ph crash" is when in a relatively short period of time the ph begins to drop and it won't stop until it reaches 5.5. This can happen literally "overnight" in a small pond. At a ph of 5.5, koi will begin to die within a few days. If this happens you can easily raise the ph by simply adding baking soda to the water. Try adding one cup for every 1000 gallons and check it every two hours until the ph is back to at least 7.0. Anytime all the fish in the pond suddenly begin to act differently at the same time you should suspect a ph crash. You can lower the ph in a pond by adding acid. Muriatic acid (pool acid) can be used, but use it very sparingly because a little goes a long way when used to lower the ph.