I have at times used a nitragone unit. its a plastic pipe filled with a nitrate remover. it works by a slow drip feed from a tap(garden hose). I fill a 50g container and it takes about 6 hrs. I then end up with 50g of nitrate free water. then I recharge the unit with dishwasher salt. it can be used many thousands of times. and Ive owned it 10yrs or so. £60.
its a good system but slow. I have now changed the way I use it. I fill the 50g container with tap water. connect a small pump to the nitragone unit and leave it all day running inside the container. when i come home from work I have 50g of nitrate free water.
the system you posted up don't say if its a rechargeable system or a replaceable internal filter? replaceable filter pads work out a lot of cash over time so beware.
wet pets.
www.romford-reef.co.uk/main1.htm
look in left panel(equipment available) then nitragone/RO systems. as the link won't take you to the right page.