I have anodes on my bow thruster and on my
Isotherm SP fridge through-hulls which I never change -- because they don't waste. I clean them up with a wire brush and that's that.
Now for the very first time, these anodes are worn, but not like the usual anode wasting, which is a clean wearing down with pitting. These anodes are as if chemically corroded -- crumbling into white powder. And a fair amount of
marine growth left over from last summer.
Should I be concerned? The
Isotherm through hulls don't even necessarily need anodes, according to the manual. They are optional; "just in case you might have any concern". And indeed they are made of copper or
bronze and not electrically tied to anything; I'm not sure why they would need anodes any more than any other through
hull needs an anode.
Maybe it's because of the fresh
water in the
Baltic last summer? I got as far as Vyborg, where there's already no
salt in the
water.
Any experience this? The other anodes (prop, shaft, hull) look normal with the normal type of wasting and at the normal rate.