A Guide to Modern Koi Pond Construction

Nexus units

These units are manufactured by Evolution Aqua and are certainly attracting the attention of koi-keepers around the country. They now come in two sizes with the Nexus 200 said to be suitable for ponds up to 4,500 gallons, and the 300 which is stated as suitable for ponds up to 7,500 gallons.

The basic Nexus unit is sold with a blue foam cartridge, but can be upgraded and The Answer fitted in the centre as shown here.

Evolution Aqua have also now produced the Eazy and this can also be fitted into the existing Nexus 200 or 300 as a retrofit. This is now the most popular option.

The Nexus is quite simple to fit, and is much smaller than a conventional filter system. The 300 is bigger than it looks so do check the measurements before getting too far with your design. The height of the unit is 954mm to the water level and with an overall height of 1070mm.
All the valves are supplied with the unit. The lids are supplied as an optional extra.

Several koi-keepers have fitted these in South Wales, and they are working well. To get crystal clear water some people are of the opinion that it is better to use a sand filter after the Nexus. There are some koi-keepers in the Midlands who have also used a vortex chamber with Japanese matting between the Nexus and sand filter.

This website was made up several years ago and some of the information has been overtaken by later products. By choice many koi-keepers feel that the Nexus Easy is the best solution for the filter system if it is within your budget. All the methods on this website will still work and are being used by many koi-keepers.

We can check out data for the Nexus, or move on to Filter media.
Also check out Fitting a Nexus to an existing pond.