Nexus 220+


Nexus 220+


Advanced filtration systems for Koi ponds now with NEW K+Media

Evolution Aqua have launched the Nexus320+ and Nexus220+filtration systems. Building on the tried and tested technology that has been ever present in the world renowned Nexus, the team at Evolution Aqua have gone even further to enhance their number one Koi pond filter.

 The Nexus320+ and Nexus220+ filters now come with a new filter media called K+Media in the moving bed outer chamber for vastly improved biological filtration and faster filter maturation. The new Nexus+ filters are also supplied “auto ready”, with factory fitted fixings already in place, making it even easier to upgrade to the Nexus Automatic Cleaning System.



Maximum pond size: 18,000 litres / 4,000 gallons
Recommended flow rate: 6,000 litres per hour
Maximum flow rate: 10,000 litres per hour
Volume of water in Nexus: 510 litres
Amount of K1 Micro in EAZY: 18 litres
Amount of K+Media supplied: 50 litres
Maximum amount of K+Media: 150 litres



Maximum pond size: 34,000 litres / 7,500 gallons
Recommended flow rate:11,000 litres per hour
Maximum flow rate:13,000 litres per hour
Volume of water in Nexus:840 litres
Amount of K1 Micro in EAZY:20 litres
Amount of K+Media supplied:100 litres
Maximum amount of K+Media:300 litres

How the Nexus+ Works

The Nexus+ filter is an innovative biological and mechanical filter system in one. Water from the pond enters the Nexus+ via the inlet into the inner chamber which works as a vortex allowing larger solids to settle out. The water then passes through Eazy filter, where finer particles are removed at the mechanical stage of filtration, thanks to the static bed of K1 Micro filter media.

The mechanically clean water then passes to the outside chamber of the Nexus+ where the new K+Media Moving Bed is located for biological treatment prior to being returned to the pond. At this stage, biological breakdown occurs through different strains of bacteria and filter feeders living on the vast protected surface area of each piece of the K+Media. These bacteria convert Ammonia and Nitrite into less harmful Nitrate. Water then passes through the exit grill into the outlet, returning back to the pond.

Nexus+ Dimensions


Installing the Nexus+

The Nexus+ MUST be installed on a solid, level base, a minimum of 1.2 metres x 1 metre. Failure to do this will cause irreparable damage to the filter and will therefore invalidate your warranty.



By this we mean that your pump is going to be used to return the filtered water to the pond and therefore your filter will be supplied by gravity via a larger diameter pipe. In this situation the water level in the filter will be at the same level as the pond.



By this we mean that if your pump is going to be used to supply the water to the filter, and the filtered water then returns back into your pond via gravity, i.e. down a waterfall, or through a large diameter pipe, this is referred to as PUMP FED (i.e. the water is fed to the filter using a pump).



Model Max Pond Size Max Flow Rate Volume of Water in Nexus Amount of K1 Micro in Eazy Chamber Amount of K+Media supplied in Bio-chamber Max Capacity for K+Media
18,000 litres
4,000 UK Gallons
4,800 US Gallons
10,000 litres/hour
2,200 UK Gallons/hr
2,640 US Gallons/hr
510 litres
112 UK Gallons
135 US Gallons
18 litres of K1 Micro inside the Eazy 50 litres of K+Media in the bio-chamber 150 of K+Media in the bio-chamber
34,000 litres
7,500 UK Gallons
9,000 US Gallons
13,000 litres/hour
2,859 UK Gallons/hr
3,431 US Gallons/hr
840 litres
185 UK Gallons
222 US Gallons
20 litres of K1 Micro in the Eazy 100 litres of K+Media in the bio chamber 300 litres of K+Media in the bio chamber


New advanced filtration media

Plastic media, for use in biological pond filters - specifically in moving bed bio reactors, was pioneered by Evolution Aqua, some 20 years ago. In recent years, other plastic media have come onto the market, usually with the aim of trying to get more and more surface area. However, one drawback to using plastic media has always been the time it takes to establish a stable biofilm – essential for good filtration.

 After many years of research, Evolution Aqua have now developed a new media that not only gives class leading surface area, but also overcomes the problem of long maturation times.

K+Media is designed and manufactured in the UK by Evolution Aqua. This advanced media, with its innovative design, and class leading surface area provides enhanced biological and mechanical filtration.

 As Evolution Aqua extrude K+Media, Minerals and Enzymes are added to the raw material. The result of this process, unique to Evolution Aqua, is a filtration media that not only outperforms most of its competitors due to its large protected surface area, but also answers the problem of how to speed up the time taken to mature your filter.


Minerals added for faster filter maturation 

During the extrusion process, Evolution Aqua add a range of minerals, along with magnesium, calcium, enzymes and salt to the raw material that is used to manufacture K+Media. The result means that K+Media will mature much faster than many other types of media.

- The addition of these minerals creates a rough surface on the media. This textured surface has a microscopic honeycomb of peaks and craters that allow waste particles to collect, and nitrifying bacteria to form.

- The minerals act as a food source for the bacteria, helping the bacteria to develop and multiply at a faster rate, further improving maturation times.

- Calcium alone has proven advantages for developing and maintaining effective bio-films.

- The enzymes that are added also help to make the media “sticky” so waste particles can adhere to media easier.

- Salt is added during the extrusion process, which is dissolved during the cooling process, leaving a rough surface on which bio-film can easily adhere.

Increased surface area 

With a new shape and profile, K+Media has also been designed to have an increased and class leading surface area, meaning an overall surface area of 1,350m2 per m3. More importantly for biological filtration, the protected surface area of K+Media is 1,025m2 per m3.  This allows a stable bio-film to form and remain intact when used in moving bed biological filtration, as in the new Nexus+.


Stable bio-film development

The shape of K+Media optimises the amount of “quiet zones” within the media where a stable bio-film can develop. Whilst K+Media keeps the integral profile of K1 Media at its core, there is an extra layer of cells and fins around the outside of each piece that enable microscopic organisms such as Rotifers and Vorticella to thrive. This is an additional benefit as competitor media do not have such “quiet zones” that would allow these higher lifeforms of filter feeders to develop. The bacteria and organisms that form within the bio-film ensure the media delivers optimum levels of biological filtration in the moving bed, which has been proven filtration technology for many years in the fishkeeping hobby.

Use with PURE Pond products 

Evolution Aqua also recommend using K+Media in combination with the PURE Pond and PURE+ Filter Start Gel to boost bacteria levels which in turn will stick to the media and speed up the maturation process even more.


Do I need an airpump for NexusPlus?

Yes, it powers the moving bed biological filter and is also vital to the cleaning process. You need an Evolution Aqua Air Pump 75 for a Nexus 220 and an Air Pump 95 for a Nexus 320. If you increase the amount of media in the outer chamber you may well need a more powerful airpump.

The correct size airpump to enable the filter media to move is detailed in the below:

  • 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

A Range Of Varieties

We breed a number of varieties of Koi each year and use our many years of experience to select the very best.

Hundreds Of Awards

We breed the finest Koi (Nishikigoi) in the UK and have won hundreds of awards for their owners over the years.

Online Or In-Person

You can buy the Koi we breed direct from us by visiting our farm in Oxfordshire, or you can order online.
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