I don't know anything about the Weston vats, so I don't know what the hole you need it to fit looks like, but if you're needing to agitate and aerate the water, could you fabricate a spray bar with a short piece of maybe 3/4" or 1" pvc capped on one end, and with a row of holes drilled along the length? On the other end you could put a female threaded coupling with a male threaded nylon barbed fitting to accept a piece of flex tubing and use a small pond/fountain pump from home depot. The smallest pumps will still flow quite a bit of water, and as long as they are kept submerged and not allowed to run dry, I have had good luck with the longevity. I just don't know if something like that would work because I don't know what the hole in your vat looks like, but if it could work it would be a lot less than $265.00!
If a man does not keep pace with his companions, perhaps it is because he hears a different drummer. Let him step to the music which he hears, however measured or far away.