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A new product in the webshop: Marks Gel Bacteria for the pond

Our new pond bacteria

Marks Koi Feed Gel Bacteria is from a gel with live bacteria, which are specially cultured to start up the biological filter and maintain optimal function. The biological filter breaks down the toxic ammonia from the pond water to less nitrite and finally to the least toxic nitrate. Plants and aeration ensure that this nitrate can also disappear from the pond water. Nitrifying bacteria in the biological filter convert ammonia and nitrite into the less harmful nitrate. Nitrate is acceptable to fish in higher concentrations and its concentration decreases, for example, when absorbed by pond plants, water changes or nitrate resin in the filter.

Under normal conditions, it takes an average of 7 weeks to restart a biological filter after winter or after cleaning the filter.

Marks Koi Feed Gel Bacteria boosts the action of the nitrifying bacteria in the biological filter, speeding up the breakdown of toxic waste products. The gel has a special formula to make it easier for the nitrifying bacteria to adhere to the filter elements. With the use of Marks Koi Feed Gel Bacteria, the start-up time of the filter can be reduced to from 7 weeks to 3 to 4 weeks. Marks Koi Feed Gel Bacteria are 100% natural and contain no chemicals or pathogens.

How to apply?

After the winter period and after cleaning or installing a new filter, the bacteria culture should be started up. For start-up, the content of one bottle of Marks Koivoer Gel Bacteria is sufficient for a pond with a volume of 10,000 L (10 cubic metres). For other pond volumes, 50 mL of Gel Bacteria should be administered per 1,000 L (1 cubic metre) of pond water. To maintain optimal operation of your biological filter during winter, it is advisable to add 10 mL of Gel Bacteria per 1,000 L of pond water every week.


The gel can be applied directly to the water or to the filter. Only for new filters should the filter system be switched off for a few hours to give the bacteria a chance to attach. When doing so, switch off your UV lamp and/or ozone device for 24 hours. You can also aerate extra, giving the bacteria a chance to convert nutrients and multiply faster.

The packaging comes in 2 volumes:

0.5 litres Marks Pond Bacteria

for 10,000 L (10 cubic metres) of pond water
€ 11,95

1.0 litres Marks Pond Bacteria ​

for 10,000 L (10 cubic metres) of pond water
€ 17,95

Should you have any further questions about our Gel Bacteria, we are of course available!

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Do you have a question about one of our products, a general question about koi food or about keeping koi? With our many years of experience, we are happy to help you!

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