Unfortunately, an error has crept in. The replacement filter cartridge has a water flow rate of 8 litres per minute, which corresponds to the water flow rate of the complete set. We will of course correct the information accordingly. With regard to the price, I would like to point out that we purchase our products from different suppliers at different purchasing conditions, which influences the price. Due to our daily prices, the price of a product can change within a short period of time. I therefore recommend that you save the item on your watch list so that you are informed by email if there is a price reduction.