I have a BC14 with a lid. I drilled a little hole on the lid and attached a cardboard funnel. Taped an auto fish feeder with pellets in it. I also had a floating ring right underneath the hole so that the pellets wont float into filter chamber. Fish learned to eat floating pellets from the ring. No issue with sinking pellets. Went on vacation for 3 weeks. BTW, I also had a DIY auto top off system. Came back after 3 weeks and everything was in tip top shape.