Koi Care Basics Blog

For any pond over 1000 gallons it is wise to use a pressurized biological sand or bead filter that can be back washed. There are pros and cons with either sand or beads.

During the backwash portion of the operation, sand, since it is heavier than water, falls to the bottom of the tank instead of flowing out through the valve with the waste. Plastic beads, since they are lighter than water, float to the top. As they are smaller than the valve-strainer’s holes, they get washed out through the valve into the waste stream. More and more beads are lost during each backwash operation.

Bead filters also have limited efficiency. Smaller beads have more surface area for good bacteria colonization, but tend to get flushed out during the backwash procedure. This doesn’t happen to the larger sized beads, but they have less surface area and thus are unable to filter as efficiently.

By under-loading the sand filters, and backwashing them more frequently with higher pressures and flow rates, you can take advantage of the greater food processing surface areas, while eliminating the chance of plugging, which can be their main fault. Many manufacturers recommendations for loading sand tend to be too high.

This causes the sand to plug the filter which is the main drawback of sand as a filtration medium.

Up-flow and gravity flow filters need to be cleaned regularly and it is a filthy job. The filter media is packed with rotting organic matter and foul odored fish waste .

As you clean and handle all the various parts of these filters you will find small, white feces-eating worms crawling on your hands and arms. Add to this the ambiance of the offensive odor described above and you don’t exactly have nirvana!

The up-flow and gravity flow filters, though inexpensive to make, cost a fortune to purchase. So, in addition to paying a premium price to buy one, you are also spending so much time and labor that you might as well have paid at least twice the price!

If you use a pressurized filter, all it takes is the turn of a handle for 2 to 3 minutes and the filter is clean. Almost like magic! This saves lots of time, inconvenience, labor, mess, and wear and tear on your Koi. It uses slightly more electricity to operate a pressurized pump, but the savings in labor more than make up for it in most pond owner’s eyes!

You can also use the waste water for your plants. It is packed with nitrogen and works even better than many of the fertilizers created especially for this purpose!

As you can see, to find the type that is right for you, you have several decisions to make about Koi pond filtration.

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