Please, is there somebody, who use oxidation catalyst (H2O2 in ceramic little bottle) in canister filter? There is this chemical reaction : 2 H2O2 > catalyst > 2 H2O + O2 I would like to know whether is good for better dissociation ammonia to NO2 and NO3. Maybe is passible use this priciple in cheaper external filter - between expensive interval filtr. Jiri Panacek Czech republic