Testing anodes at home?

[ProfitOfDoom]

I just painted my drive the other day,and im going to put on my new anodes in the next few days. So when I put these on I have to make sure the entire area where the anode sits is down to bare metal? Or just a small area where the bolts hold it down?
I took one off before just to see what I was dealing with and from what I seen " I didnt clean or anything,so its hard to tell"
But it looked like the surface where the circle anode is under the cavatation plate looked to have paint and wasnt all bare,But the anode was all corroded,so it appeared that it had worked?
So after I get them on,Is there any way to test them on the trailer? I read about 2 ways to test to see if its working,one was just to check if power was flowing from the sender unit,and the other where you had to put a tester probe on a battery and drop the other probe in the water near your drive to see if you get a reading.
I m going to check everything and clean everything I clean,but I sure would hate to put her in the water,only to discover that its not working and then have to pull it out again,So I was thinking would the test work if I submerged what I could in a plastic garbage can of water and then try that test?
On the curiuos side of this,,how long would a magnesium anode have to be in the water before you see/feel signs of corrosion on them?

 

[Stray Cat]

The bolts will bond the sacrificial annodes to the drive, just clean the area where the annode fastens to make certain the bolts are pulling it snug. There are a lot of variables as to how long a magnesium annode has to be in the water before you know it is working....mine lose their smooth finish after 2 months. If you really want to know how much an annode has eroded annually, measure them when they're new, then measure them again after the season.

Regarding the test of the Mercathode system, as you know from your earlier thread you can test the controller out of the water, but you have to dunk your boat to get an accurate reading while using the reference electrode that you dangle behind the prop while it is connected to a multimeter...even if you could submerge your drive in a plastic bag (that would make for some good pictures :lol the results wouldn't be valid as you need to let the whole boat soak for a few days before you take a reading with the reference electrode.