How to tell if my anodes are aluminum or magnesium?

[milestan]

purchased a used boat with an Alpha Gen 2. For the most part, the anodes are in good shape, except the carrier one is starting to look a bit pitted. I'd like to replace it, but I can't tell if it's aluminum or magnesium. I run in freshwater only. I'd buy all new magnesium to replace them if they're aluminum, but seems like a bit of a waste if they're already magnesium. Is there a simple test I can do to find out? By the way, I know they're not zinc because they'd be about twice their weight. Unfortunately, magnesium is just a little light than aluminum, and it's kind of difficult to tell.

 

[Bondo]

Re: How to tell if my anodes are aluminum or magnesium?

purchased a used boat with an Alpha Gen 2. For the most part, the anodes are in good shape, except the carrier one is starting to look a bit pitted. I'd like to replace it, but I can't tell if it's aluminum or magnesium. I run in freshwater only. I'd buy all new magnesium to replace them if they're aluminum, but seems like a bit of a waste if they're already magnesium. Is there a simple test I can do to find out? By the way, I know they're not zinc because they'd be about twice their weight. Unfortunately, magnesium is just a little light than aluminum, and it's kind of difficult to tell.

Ayuh,... Welcome Aboard,... Don't worry 'bout it....

So long as it's atleast 1/2 there, it's doin' it's job....

Just abit pitted is no reason to replace it...

 

[Don S]

Re: How to tell if my anodes are aluminum or magnesium?

Magnesium is fresh water only, aluminum can be used in fresh or salt water. When it gets to 50%, install the magnesium as it does a little better. If you aren't seeing any corrosion on the drive, whatever you have is fine.