It seems the water should be drained from the bottom where released particles would fall, pass through the filter, then be pumped back in at the top.
I'm not an engineer but this doesn't look logical to me.
It seems there is a lot more thought than that which went into the Degritter. From the Degritter website:
"The active filtering solution works by circulating water through the filter and then back into the bath while your record is being cleaned. Water is pulled into the filter from the top of the tank in order to remove all floating dust and particles. Heavy particles that settle at the bottom will be pumped out to the external water tank, which has a dedicated sediment section."
It looks like they have all issues covered.