Provided is a replacement basket configured to house a pellet bed through which fluid may pass. The flow direction of the fluid prevents the bed of pellets from fluidizing within the replacement basket. Provided also is a system using the replacement basket and a method of providing pellets in the replacement basket. According to example embodiments, a replacement basket may include a top surface portion, a bottom, and at least one vertical wall with a hole. The hole is configured to allow a flow of fluid to enter the replacement basket. A plenum, below the pellet bed, may allow a flow of fluid to proceed through the pellet bed in a downward direction. A central pipe may be provided in the replacement basket to allow the flow of fluid in the basket to exit the replacement basket.