I need help understanding how the vinyl tubing will connect to the bulkhead. From listening to others sounds like the tubing should go over the bulkhead but I just got my bulkheads and tubing(recieved the stiff instead of the flexible ) So they are sending the right stuff. Anyway from looking at the bulkhead and tubing the tube wont go over the thread but in. I asked the guy about it and he said there is a fitting to go in the bulkhead that the tube will slide over. Help I don't want leaks! I am going to use silicone on it but does the tubing part sound right?