As others have mentioned above, I would be concerned about the abrasive effect of the clay particles being embedded in a soft material and abrading the harder material in the bearing.
On a house move, we once acquired a pond including a pump to run a fountain. This ran extremely roughly – on investigation, it used an impeller using a stainless steel shaft located in cylindrical recesses in the thermoplastic enclosure. The plastic recesses were not significantly worn, but the stainless steel was worn down to near half of its original 1/4" diameter!
So don't expect SS to wear well if the application does allow clay slurry into a softer bearing!
Many years later, I still have 3 off 24V 50W pond transformers attached to 50W halogen machine lights (bought cheaply at the Midlands model engineering exhibition a few years ago) to light my machines. The pond pumps are history…..
Martin