So my normal routine yearly has been to replace the tube, duckbill and the compression fittings. I was seeing a reduction in the amount of chlorine dosed and upon inspection found that the d shaped shaft had rounded the hole in the roller assembly. This caused the Stenner to sound normal but not function as expected. Just thought I would share, I’ll be keeping a spare on hand I only run my Stenner 5-40min per day year round. Lasted about three years.