Invisible / Hidden filter for tanks up to 100 litres (or as an additional filter to reduce nitrate)

This filter is made from the 'Okiishi' OR/5 resin rock which is 46x24x15cm and contains the following:

NEWA oxygenating water pump (450 lph)
Approx. 1kg of Biogravel in mesh bags
Medium density foam
Coarse density foam
3 x 'S' hooks 
Carbon pad (optional use)
Fine pad (optional use)

The Okiishi OR/5 resin rocks were made by Unipac and were recently discontinued due to the high production costs.
Total cost for everything included would be well over £100 but we are selling a limited amount (10) of this a ready-made filter for under £100.

The 'S' hooks can be bent to allow for thicker / thinner tanks to get a close fit between filter and glass.

For buyers outside the UK please bear in mind the pump is 240V and to use it from a domestic 110V system you will need a step up / down converter plug or transformer.

This video I made a while back shows a bigger version of this filter and it has a rotating outlet on the pump. If you want a rotating outlet then it is available here but they occasionally show up on Amazon (where they are generally more expensive).