Well, I think it can be as sound waves, electrical / magnetics fields, etc. Distance is always a concern (at least at macro levels, in the quantum levels all goes weird ).
If distance is a concern ... one thing is to have the vibrations source at the bottom and almost parallel to the record and another one vertically (direct radiation) and really close to the record.
One thing you really help me to understand is about filters and the dirt in the water ... you aren't really moving / circling the water, so the dirt naturally must go to the bottom. Filters are not necessary with standard water replacement times.
If distance is a concern ... one thing is to have the vibrations source at the bottom and almost parallel to the record and another one vertically (direct radiation) and really close to the record.
One thing you really help me to understand is about filters and the dirt in the water ... you aren't really moving / circling the water, so the dirt naturally must go to the bottom. Filters are not necessary with standard water replacement times.