So I have a rubbermaid stock tank 100 gallon and I tried to replace the bulkhead after nothing it kept leaking. So in theory I figured I would put a 1 1/2 on there and just sand the hole out slightly, well there is a inside lip that I did not notice so when I go to screw the bulk head down it won't fit, what I should of done is just use a 1 inch or 1 1/4 but too late now, essentially the hole is to big now... any suggestions?