Freshwater - calcareous buildup on propshaft

[mcswain29]

Any tips/tricks out there to mitigate buildup on running gear surfaces?


-Austenitic (non magnetic, but actual alloy unknown) SS prop shaft
-Mg shaft collar anode as well as Beneteau style propshaft nut Mg anode
-1.1 to -1.2v on an ag/agcl half cell in all possible combination of conditions (at and away from marina slip, AC power on and off, DC powered on and off, etc)
-located in Eastern Lake Ontario, freshwater
-boat sits at the slip for max 5-7 days at a time



After a season, I end up with a white calcareous buildup on the propshaft and prop. It's ugly but is removable with off the shelf descaling chemicals (CLR, or Zep, etc) but my main issue is the abrasive wear it causes to the cutless bushing, as it does form on the bearing surface of the propshaft


Everybody else that I see using (incorrect for freshwater) zinc anodes stuff looks clean as a whistle on haulout


Perhaps a switch to Al anodes?