I concur, the pellets should be tumbling aggressively at the surface with a good amount of flow through the rest. I use rio 1400 pump(I have used many different rio pumps, they have been amazingly reliable and affordable.) the pump is rated for around 320 gallons per hour with 1 foot head pressure through a nextreef smr1 reactor. IMO that is a very good set up. I have used two little fish, nextreef mr1 with moded screens for top and bottom but I still believe a proper bio pellet reactor should be employed to get the best result.
