Evolution Aqua K+ Media 50 litre is a supplement to increase the volume of biological media in Nexus Plus Filters. By adding extra filter media, more surface area for filter bacteria and other micro organisms is provided, increasing biological filtration performance.

Nexus Plus Filters are each supplied with a basic volume of K+ Filter Media. However more may be added as follows:

• Nexus220+ is supplied with 50 litres of K+ Media / a further 100 litres may be added for a total of 150 litres.
• Nexus320+ is supplied with 100 litres of K+ Media / a further 200 litres may be added for a total of 300 litres.

K+ Media is available in 25 litres and 50 litres bags:

• Evolution Aqua K+ Media 25 litre
• Evolution Aqua K+ Media 50 litre

The addition of Evolution Aqua K+ Media 50 litre or 25 litre bags allows you to add extra K+ Media incrementally to optimize the efficiency of your filters based upon you fish stocking densities and feeding regimes. If you increase the amount of K+ Media in your filter it is important to ensure you have a powerful enough air pump to circulate it:

• 50 – 75 litres = Use an Air Pump 75
• 75 – 100 litres = Use an Air Pump 95
• 100 – 150 litres = Use an Air Pump 130
• 150 – 300 litres = Use an Air Pump 150

Plastic filter media were pioneered by Evolution Aqua some 20 or so years ago. Since then, their extensive scientific research has led to the development of new ‘K+ Media’ which incorporates several advanced design features:

• The shape has been optimised to increase the amount of ‘Quiet Zones’ within the media where a stable bio-film can develop. This has been achieved by adding of an extra layer of cells and fins around the outside of each media piece. In addition to increasing the available surface area for filter bacteria to thrive, the new design also provides a suitable habitat for larger micro organisms such as Rotifers and Vortcella, that play an important role in breaking down small solid waste particles.
• Salt is added during the extrusion process, leaving a rough surface to improve bio-film adhesion. Enzymes are also added to make the media ‘sticky’ to further aid bacterial adhesion and reduce the bio-film maturation time.
• Minerals such as calcium and magnesium are added which are an important food source for filter bacteria, helping them multiply faster. Optimum biological filtration performance is only reached once filter media is fully colonised.

PURE+ Filter Start Gel should be added to your filter media to speed up the initial maturation. PURE Pond should then be used each spring to boost the bacterial population. Bacteria levels tend to deplete in winter due to reduced organic material entering your pond as a result of reduced fish feeding and metabolic activity. As you start feeding your fish again with warmer water temperatures, you also feed your filter bacteria with waste allowing larger populations to be maintained.