Koi Care Basics Blog

What is healthy Koi water? This is an extremely important question because the water quality in your Koi pond is the most important factor affecting the health of your fish.

You can determine if the quality of your pond water is sufficient for your koi if the following criteria are met:

1) The water in your pond is free of chlorine and other chemicals such as pesticides, heavy metals, organophosphates, etc.

2) There are undetectable levels of ammonia and nitrite in your pond.

3) Water hardness, pH level, and temperature are correct.

4) There are low levels of particulate organic compounds (POC) and dissolved organic compounds (DOC) in your pond and…

5) Your Koi water stays consistent in it’s stability.

If you use tap water in your pond it has probably been treated with chlorine. Chlorine can be fatal to your Koi. One way to make it safe is by “aging” chlorinated water before placing your Koi in it. How long is long enough? Make sure you wait AT LEAST 24 hours before placing your Koi in tap water.

If you use subsequent additions of tap water in your pond make sure that the amount is a small percentage of the total volume of pond water. Also be sure to test for chlorine levels after each addition.

The next deadliest contaminant in your Koi water would be ammonia. You always have to be careful of ammonia because the main source of the ammonia in your pond is your Koi themselves! Fortunately ammonia can be broken down into it’s less harmful components through the process of biological filtration.

Since certain types of beneficial bacteria break down the ammonia, the highest risk for ammonia contamination is in newer ponds. This is due to the fact that they haven’t yet developed large enough colonies to neutralize the ammonia.

Since the danger from ammonia in new ponds is so serious I recommend that you check ammonia levels every day until they stabilize and make frequent Koi water changes, even daily if necessary. Once your ammonia readings stabilize you will be able to relax a bit!

An acceptable level of ammonia in your pond is actually ZERO!

Even very low ammonia levels (<.1mg./liter) are extremely irritating to Koi fish, especially to their gills, and higher levels can lead to skin and gill hyperplasia. In gill hyperplasia the secondary gill lamellae become swollen leading to breathing difficulties. Serious gill disease and death occur when high levels of ammonia contamination are reached.

As you can see, even in the case of just these two factors of  water quality it is essential that you monitor and maintain your pond so that your fish have healthy Koi water!

Alan Deacon
KoiCareBasics.com

What is the optimum Koi pond alkalinity level?

Generally levels of 50-170 are what is recommended although some Koi keepers are keeping their pond levels even higher at around 180. The reason for this is that alkalinity will decrease over time as the good bacteria in your pond consume bicarbonates which slowly decreases alkalinity.

Alkalinity can also be referred to as carbonate hardness or German carbonate hardness. It is the measure of the concentration of the capacity a solution has to neutralize acid without changing pH. It both maintains and controls water pH. Koi pond alkalinity level can be measured in parts per million of calcium carbonate (ppm of CaCO3), milligrams per liter (mg/L), grams per cubic meter or degrees (dKH).

Test kits measure alkalinity as carbonate hardness or dKH and often in degrees of German Hardness (odH).If you want to convert German Hardness to parts per million (ppm) you can simply multiply by 17.

In spite of the fact that that a pH of 7.4 is best for Koi fish it can be a good idea to keep th pH level a little higher. pH levels can crash quite quickly when your alkalinity (KH) begins getting lower than 80 ppm. Since alkalinity is the buffer that helps maintain pH it is important to test it regularly. You may find that it’s better to keep your Koi pond alkalinity level above 100 or 120 pm. It will give you a bit of a buffer zone to help maintain your pH.

There are several ways that you can add alkalinity to your pond. One way to do this is through water changes. This can help introduce new minerals and can also increase alkalinity. However, if you have softer water it’s alkalinity can be less than 80 ppm. You can increase both the pH and KH by adding Arm & Hammer Baking Soda to the water. One third cup of baking soda per 1000 gallons of water will raise the KH level by 25 ppm.

Make sure that you take care not to raise the KH level more than 25 ppm a day. If you do it will cause undue stress to your Koi. An exception to this is if you are losing fish to a pH crash. A pH crash is when the pH level hits 5.5 or lower. In this case you have nothing to lose by adding a bit more baking soda to the water.

Water doesn’t have to have a high pH to have high alkalinity. Alkalinity is related to the dissolved amounts of calcium, magnesium and other compounds in the water. This is why alkalinity tends to be higher in hard water as opposed to soft water.

There are various reasons that Koi pond alkalinity level will decrease over time.

Decreases occur naturally over time due to bacterial action which produces acidic compounds which combine with and decrease alkaline components.

Ponds with fiberglass construction or vinyl liners tend to exhibit a higher decrease in alkalinity over time and might need supplementation to help them maintain proper levels. Alkalinity can be raised by adding calcium carbonate, oyster shells, concrete blocks, egg shells or limestone.

High alkalinity can be prevented by routinely changing out the water if the water you are replenishing with has a lower alkalinity than the pond water.

An established pond usually maintains an equilibrium in it’s pH value if you keep it clean by removing sludge and any organic materials before they have time to decay. Scheduled water change outs (i.e. 10% / week for small ponds, less for larger ponds) can also help maintain proper pH and Koi pond alkalinity level.

You should definitely purchase a test kit and use it on a regular basis!

Alan Deacon
KoiCareBasics.com