Frequently Asked Questions

• The pump could be too powerful, so the Nexus+ is being emptied before the pond refills it by gravity.

• There could be a blockage in the transfer port between the inner and chamber and the outer chamber. You need to back flush it. You can download the instructions to backflush here.

• The Eazy needs cleaning. Or the Eazy’s steel screen needs cleaning. Beware of sharp edges!

Maximum recommended flow on the 220 is 10,000lph and the 320 is 13,000lph, however suggested flow rates are lower. Slower is better for fine removal and clearer water. Aim to turn over your pond volume every two to three hours. The Evolution Aqua Varipump range are adjustable, and consume less energy when you turn them down.

Yes, it can easily be adapted to either filtration method by simply swapping the supplied rubber boots.

The Nexus 220+ comes with 18 litres of K1 Micro in the Eazy (inner chamber,) and 50 litres of K+Media in the outer chamber.

The Nexus 320+ comes with 20 litres of K1 Micro in the Eazy (inner chamber,) and 100 litres of K+Media in the outer chamber.

For older models, the 300 and 310 contained 40 litres of K1 in the Eazy, and 30 litres for the 200 and 210.

Don’t change the amount of media in the Eazy as this affects particle capture, and ease of cleaning. The amount of media in the outer chamber can be increased however by up to 150 litres in total in the 220 and 300 litres in the 320 models.

Only increase the amount of media in the outer chambers for heavy stocking and heavy feeding. Note that if the total volume of media is increased in a newly set up filter it will take longer to mature, as there is more surface area for bacteria to colonise and the biofilm will be more thinly spread.

Media can be purchased from your Evolution Aqua dealer.

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

The Automatic is a separate system which can be fitted to Nexus filters, to enable automatic cleaning. By combining timers and automatic valves, Nexus can be converted and set to clean itself, as little or as often as required. It can be set to clean at night or while you are on holiday, and once set it means total hands-off cleaning. The more your filter is cleaned, the more that waste is removed from the system before being broken down. That means a cleaner pond, cleaner filter and healthier water.

The Automatic System can be fitted to all Nexus models manufactured after 2006, and both gravity fed or pump fed models. It can be fitted by the user or a pond filter installer. The Automatic system still requires a Nexus, airpump and a water pump, along with a power supply. During cleaning the Nexus will expel dirty water to waste, so an auto top-up fitted to the pond (not supplied,) is advised if the filter is set to clean frequently.

The return pipe is 40.5cm long in the 220 and 46cm long in the 320. This is a length of 4" pressure pipe which is factory fitted during production to the return chamber of the Nexus and sets the level of the water in the Nexus. It is removed when using the Nexus in a gravity fed pond. This can be quite difficult to retro fit as the hole is quite tight, you may find it easier using 110mm soil pipe as this has a slightly smaller outer diameter.

Nexus 220+

  • Total volume of water 510 litres / 112 UK gallons / 135 US gallons
  • Outer chamber 405 litres / 89 UK gallons / 107 US gallons
  • Inner chamber 105 litres / 23 UK gallons / 28 US gallons

Nexus 320+

  • Total volume of water 840 litres / 185 UK gallons / 222 US gallons
  • Outer chamber 635 litres / 140 UK gallons / 168 US gallons
  • Inner chamber 205 litres / 45 UK gallons / 54 US gallons

Remove the outside union on the waste ball valve, open the valve, if no water pours out the blockage is under the Nexus, carefully push a suitable stick (such as a cane) and release the blockage, you can also remove the Eazy and access the pipe from the 1.5" hole in the bottom of the Nexus inner chamber.

You first need to remove the sticker of the far right side box and change the dial with a small screwdriver from 5 to 4, this will extend the cleaning time by one minute.