It may be that case that we have an encrustation on this anode rather than corrosion. We haven't verified the weight but dimensionally the anodes are the same after we scrape away the crust.
I have a condition with vertical turbine pumps in a wetwell pumping chlorinated water. Chlorine residual is 3-5 mg/L. TDS is about 1200 mg/L. All the pumps are fitted with anodes on the pump column. The anodes on the jockey pump (1 of 4) shows extensive corrosion on anode(fully crusted over)...