Hi all
I clean my co2 diffusers every other week, otherwise the bubble size is not uniform (I only want co2 mist coming out of them, not bubbles that can reach the surface). No matter if it is an expensive or cheap model. Good cleaning is a must IMO. I just remove the diffuser when I begin my WC and soak it in bleach for 20 minutes approx (actually the time I spend doing the WC). I also use H2O2 if I see green algae growing on the ceramic disc, but just as a fast solution (rise the diffuser over the water level and fill it with H2O2. Some minutes are more than enough and I don't even wash it with tap water).
Jordi