2008 FS234 with 350 mercruiser EFI battery questions

[Mikefs234 0]

Hello folks,

purchaed a used fs late last year, boat has duel batteries with an on/ off switch, was expecting a different switch configuration to isolate the two batteries. From what I can gather is that the two batteries are wired in parallel. I will go down to the storage to determine if there is a blue sea regulator as to charge both batteries independently. But onto the real question, Manuel says to use standard marine starting batteries, group 24, 750 CCA. Has anyone run AGM’s starter/ deep cycle combo’s? Any issues? Or stick with what the manual says?