Hi Paul,
Could I ask you why you would want to actually remove your nitrates in a planted tank?? Most folks have difficulty maintaining high enough nitrate levels as it is. If you read the atricles and threads on this site you'll find that the general concensus is that the lack of sufficient levels of nitrates is a contributing factor to poor plant health and of algae proliferation.

Adding a nitrate removing aparatus to a planted tank is therefore counterproductive. My advice would be to save your €25 and buy more plants and more Potassium Nitrate.

Cheers,