I had one valve that did not leak but was hard to open even after many manipulations and did follow this video and used silicone spray to lube it. Being a hoarder of screws and bolts I did have a screw that could be used to close the hole I drilled. I also had a o-ring that would fit the screw so I did not have any leakage around it. It worked for me but may not for others. anyway since I have 3 tanks I am going to redesign the connections so I can empty all through one connection. Still would have 3 valves but not need to move hose to empty.