Product review (5 stars): Change Cartridge/Material as Recommended
This worked perfectly with my Air O Swiss. For like three years I didn't even realize this thing needed to be changed; I thought it was just the hydro cell that needed changing. When I switched out my old cartridge the material inside had turned green! You definitely need to be changing this cartridge! Will be doing so every 2 months as recommended. I am going to look into whether or not they sell the refill material so I can just switch that out instead of buying a whole new cartridge so it's less waste. But after so long with the old cartridge I definitely needed a fresh one.