I have a 5 gal cylindrical smoke oil tank with the pick up port centered in the rear end. I am using a flexible tube attached to a fitting as the pickup and need to weight the end so it will follow gravity during aerobatic maneuvers. The fitting is about the size of a 1/2 in drive socket, so what ever is attached to the flexible tube must pass through this opening. What would you use to weight the end of the flexible tube and how would you secure the weight to the flexible tube? Other than the normal flop tube I’ve found at ASS (which is too stiff to enable vertical maneuvers) any thoughts on how would you weight and secure it to the end of the flexible tube?