Re: need a hand from those who have a maxant bottling tank
It is not a bolt, it is a pipe plug. Measure across the hole, if it is just over 1/2", it is a 3/8" plug. If it is right at 3/4", it is a 1/2" plug. You can get these in brass at your local big box hardware store, or you can go to a pipe supply house and get one in stainless steel which is probably what came stock. Pick up some teflon tape to wrap the threads while you are there.
Thankfully, the bees are smarter than I am. They are doing well, in spite of my efforts to help them.