I got a water tank (like this) installed which is leaking from an unused outlet at the bottom. The fitting is as shown in the figure below, it looks somewhat like a bulkhead installed in reverse:
Pic from outside:
I think that the water is seeping out from either side of the outside gasket. The obvious way to fix this is to tighten the nut on the inside. However I can't tighten the nut from the inside because the tank has a narrow opening and is very deep. I will have to drain it, disconnect it, move it on its side and then crawl into it, which is a lot of work and risks damaging the tank.
I am asking if anyone has ideas or knows of tools which provide an easier way to do this.