Should I get fresh water cooling?

[toyota40runner]

i am moving back home to hawaii, and i am bringing my 2001 san. I am wondering if i should get fresh water cooling. I do not have to worry about much salt content, but more so the minerals in the water scaling the block. My old boat over there had it but i am just wondering if it is too late to get it now that my boat has over 300 hours. I read somewhere that once any kind of scaling has built up inside the block that it is not a good idea to install fwc. it also appears to me that the transmission is stil cooled by raw water. I feel like i should just save the money of getting fwc. Flush the boat everytime and every couple years run descaling flush through her. Any opinions?