Digestive/Poop Issues?

I mentioned that my boy, Barkley has been having some digestive issues lately. He's still his energetic self, and eating and drinking normally. His poops were soft, mushy, and sticking to his cage, so I took away his pellets and uped his hay. I would give him a shredded wheat with some activated charcoal on it while that was happening too, with that being his only "treat". After about a week of that not helping, I took him to the vet. They prescribed him panacur, which did help with his soft stool. Now, his poops are still rather large, and a dark green in color. I'm kind of at a loss with what to do. Like I said, he's still his normal self. Does he need another vet visit? Has anyone had a problem similar to this? Any tips or suggestions what to do would be appreciated. I can attach some pictures if needed.