Well from what I understand those two columns are not meant to take on much solvent. Those are to by pass for recovery from top of material columns no?
I used that model for 3 years and never had a clog on the recovery coils. I only ever used sieve in the cups, if I remember correctly I also had a convo with a ets tech who told me the cups was good for the sieve.how would you put a sock if the dip tube goes all the way down to the base of the screen gasket covering the beads?