For whatever critters or sump monsters you keep down there, do you specifically add food for them or just let all the leftovers flow through and get eaten? I've added 4 peppermints to my sump, which has plenty of Aiptasia, but I'm considering dropping a few sinking pellets in there just to keep the shrimp happy. Although I also don't know if that is necessary since I run a filter-less system, so whatever goes into the overflow goes all the way through the sump (if it doesn't flow up to the top in the standpipe chamber and stagnate there.
