I am diving a ChOptima and so far I have only used it with cartridges. I would like to know how you are using the dust filters when using sorb instead. I understand that the purpose of filter scrims is to provide a barrier to dust and particles from absorbent packed in the scrubber. Do you use them (they are not mentioned in the ChOptima manual)? If yes, both at the top and bottom of the canister? Thanks for sharing your experience on this.