My Stenner pump stopped pumping chlorine into my pool, and I discovered a small crack in the tube. I went to replace the tube with the spare that came with the pump only to find out that it was about 3/8 to 1/2 inch shorter that the cracked tube. I couldn't expand the roller assembly to make the tube have tight contact with the outer housing. I ordered 2 new tubes, hopefully I won't have any issues with them. Has anybody else experienced anything like this?