I have a relatively new Python water changer that has worked very well until yesterday. I had trouble when I began to use the suction setting to empty the tubing at the end of my water change session.
As it turned out the piece that attaches to the sink was not really tight at the other end where it screws into the body of the venturi mechanism. This allowed air to be pulled in and so suction dropped greatly. It looks as if that piece is meant to screw tightly into the body however I could see no way to do that easily. On the faucet end when you look inside the opening you can see a large hex shaped female receptacle but I have no tool that could come close to fitting in there.
Is there a trick to tightening it?