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Black foam cartridges (12"x 4"x 4")"

Black foam cartridges (12"x 4"x 4")"

Regular price £9.16
Regular price £9.21 Sale price £9.16
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Why do i need

Our brushes are used in filtration systems in fish farms, hatcheries, public aquaria, domestic fish ponds and research institutes in this country and abroad. No other filter medium is as widely used or has been as extensively tested and proved.

How do they work

Whichever installation design you choose, the method of water introduction to the chamber will have an effect on the efficiency of the brushes. Generally the water should flow into the chamber at slow speed rather than being jetted in under pressure. Water travelling at high speed not only causes turbulence, which will disturb settled material, but it can also wash off some of the waste which has been trapped successfully in the brushes.

How to use

Before purchasing Black Knight brushes, you should decide what type of filter design will be best for your pond. How to use Black Knight Filter Brushes If you have a small pond with a few goldfish and a couple of koi then a single chamber with three to six lines of brushes will be ideal. For a more demanding situation, it will be necessary to use a much larger chamber or to link two or three together. These can all contain brushes or you can use them in the first and second chambers and then use a stone medium such  Alfagrog in the last chamber.
When a significant amount of waste has built up on the brushes, it should be flushed away. The brushes should be flushed using buckets of pond water. Cleaning in this way will retain most of the beneficial bacteria that live on the brushes but the rotting waste is removed and cannot do any more harm to the water quality.
  • Experience

    We have over 40 years of experience in the industry

  • Koi Kare


    We are koi keepers too!

    We share the same passion as our customers

  • Availability

    We are only a phone call or email away. Do not hesitate to ask us questions - we love sharing our knowledge!

  • Competitive Pricing

    We regularly review our pricing to make sure our rates are fair for our customers

Frequently Asked Questions

How Much Is Delivery?

Our delivery is free for any orders over £100.

For all orders under £100 delivery is £4.99.

How Do I Make A Return?

To start a return, you can contact us at If you have a valid return instructions will be made on how to make the return.

Please do not post a return without contacting us first.

What Is The Best Way To Contact You?

The best way to contact us is via our contact page here.

How Soon Will I Get A Refund If I Make A Return?

Refunds will be processed within 7 days of us receiving and checking the item.

Need Advice?

If you need advice or help with what products to buy, please reach out to us on our contact us page.