Hi to all!

I have a 1999 Rinker Fiesta Vee 242 with 5.7EFI Alpha One. This is the first
year the boat has lived in the water in Lake Michigan. i am starting to see
my zincs wear away. They are the original zoncs and have been in salt water.
My questions:

1. Since we are now "living" in freshwater, should i install a Mercathode
system?
2. How can I test for stray current without purchasing an expensive tester
from MerCruiser?
3. Should I also protect my shore power system? - I leave the boat plugged
in with the refriderator and battery charger running.

Thanks for any and all responses!

Dave Alonzi
"Pier Pressure"