I keep my boat part season (3 months) in fresh water and part season in brackish (1.5 month). Any suggestions on what type of anodes to use, Magnesium, Aluminium or Zink. If I go with Magnesium, will they last the 6 weeks in brackish water? Boat is in the water at all times (during season).

I run in both as well and was told to go with the higher salinity anode in each case, i.e.
fresh + Brackish - Aluminum
Brackish + Salt - Zinc