$399.00 NZD
GST included in the price

Our revolutionary Maelstrom filters set a new standard in pre-tank rainwater filtering. Filtering multiple pipes at a single point, the Maelstrom’s unique U-shaped filter keeps leaves and debris down to 180 microns out of your rainwater tank. They also significantly increase your water catchment efficiency, even at high flow rates (96% at 10 litres per second in wet systems).

How it works:

  • Rainwater enters the Maelstrom through either of the horizontal-facing couplings.
  • The rainwater then enters the Primary Filter (J). The unique curved filter slows the velocity of the water by changing the direction of its flow.
  • Surrounding the Primary Filter is a Secondary Filter (C), comprising of a nylon mesh bag which filters fine particulates larger than 180 micron. This filter assembly is easily removable and will require periodic maintenance
  • The filtered rainwater then continues to move through the Maelstrom to the Filtered Water Outlet (F) and into the rainwater tank or pipe (if attached).


  • Primary Filter: 2mm (0.08") Aperture, Polypropylene
  • Secondary Filter: 0.18mm (180µm) Aperture, Nylon
  • Mosquito Proof Screen: 0.955mm (0.04") Aperture, SS316
  • Inlet & Outlet Pipe Size DN100 (110mm OD) / 4” OD
  • Coupling Flexible: EPDM
  • Body & Base Plate: ABS, Polypropylene
  • Base Plate: Fits 500mm tank opening, cut to fit 400mm or 300mm tank opening

Performance Data 
Water Catchment Efficiency @ 5L (1.32gal) / second* 99%
Water Catchment Efficiency @ 10L (2.64gal) / second* 96%

Features and Benefits:

  • A single point, tank-top filter with a ground breaking U-shaped design. 
  • The 180 micron filter screens particles 5 times smaller than is achieved with a standard tank screen.
  • Reduces the hassle of cleaning leaf and debris build-up through Self-flushing.
  • Blocks out light that supports algae growth.
  • Is a versatile product, able to be installed in a variety of pre-tank locations.
  • Reduces frequency and cost of tank cleaning by lowering common sediment build up through cleaner tank water.
  • Mounting plate fits 300mm, 400mm and 500mm tank openings, or can be used for mounting in-tank, on wall or in a pit.