The UrSpring filter must be changed every three years, it costs 850 USD excl. sales tax. With a little manual skill, the filter of the UrSpring can be changed yourself. The required Allen key is included.
The AroxBags of a BioFilter, i.e. the self-exchangeable bags in which the filter media are located, cost between 219 USD excl. sales tax (AroxBag AntiTox for reducing chlorine by-products, drug residues, pesticides, hormone-like substances), 469 USD excl. sales tax (AroxBag AntiArsenic for removing arsenic) and 390 USD excl. sales tax (AroxBag AntiCal for limescale protection) and must be replaced every 2 years at the latest.