Anode Consumption Rate

[TugboatEng]

Is there a quick and dirty way to predict anode consumption rate after a change in materials? I have a 90/10 copper nickel heat exchanger in salt water. It's currently consuming 100 lbs of zinc in 12-14 months. I need to extend the anode life to 24 months. I was considering switching to Swedish iron anodes of roughly the same dimensions.

 

[EdStainless]

Pure Zn is likely to be giving you more voltage than you need. What potential are you seeing? Will iron give you enough? What about some of the Zn anode alloys that will have a lower potential than pure Zn, but higher than Fe?


= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed

 

[TugboatEng]

We recently opted to electrically isolate the cooler from the steel hull of the boat. This comes at the recommendation of the manufacturer to reduce biofouling. This brings a second question. Would switching to an iron anode defeat the improved biofouling resistance by reducing the potential?