My Magnum 350 filter is going on 6 years old with replacement of only
o-rings and gaskets. It has been making a 'rattling' or 'buzzing' noise for
many months that I don't remember. It is working hard pushing water
through a CO2 reactor. It could be air or CO2 in the impellor area, but I
don't know.

Any idea about this noise?

Any idea of life expectancy for this filter?

Thanks

Dick