The Silvertron does not include polarity reversal. A stirrer is also not included, but many magnetic stirrers are available at Amazon.Com.
It is not a problem cleaning the electrodes, so no big deal. The amazing design more than offsets the lack of polarity reversal. I found the ideal method to clean the 1 oz silver bar is a Scotch Brite scrubby sponge.
Another important fact: The negative electrode (cathode) never wears down, and can be any metal. Stainless Steel is the best metal for the negative electrode because it is far easier to clean. Electrolysis eventually strips away all of the metal from the Anode (positive electrode). Therefore it makes sense NOT to do polarity switching and to use a 1 ounce bar for the anode. A 1 Ounce silver bar can last a lifetime of normal use by a family, and of course a stainless steel cathode will last forever.
IMO, polarity switching is a marketing gimmick to sell product, where the ideal solution is a 1 oz bar for the Anode (+) and stainless steel for the Cathode(-). The excuse given for polarity switching is so the anode & cathode wear evenly, but hide the fact that expensive silver is not even needed for the cathode. They make more money selling 2 silver wires instead of one silver & one stainless steel.