The Athena has filter#1 and fitler#2. The front of the machine shows a counter for each filter. When the counter goes up to 9999, it is time to change the filter.
Filter#1 is on your left=sediment filter Filter#2 is on your right=biostone filter
How to remove filter. 1) Open the cover to have access to the filters. 2) Push down on the filter, remove and replace with new filter. 3) After putting in the new filter, press the white square button ontop, hold it until you hear the beep, and you see the counter 9999 reset to 0 4) Flush your new filter for 5 minutes before using.
