i cant say that the carbon causes fin erosion or in some cases with SA cichlids HITH disease, (i havnt heard of or seen any scientific proof of this....yet)
change out the carbon or get rid of it completely and take up some chemipure or purigen, since your tank is a 375 gal chemipure of purigen might cost your afew extra bucks,
but again you dont need either, but it does help.
from personal experience i use vitachem to reverse any fin errosion or HITH disease, my severum had both, and now they are gone, but her left perctoral fin never seems to heal, its been split ever since i got her in a LFS about 3 years ago. but other than that she's a beautiful fish.