Maybe glue this (with LOTS of pipe glue) hub-hub repair to the grey tank.
https://www.homedepot.com/p/Charlott...00HD/203393300
Then use this 3" pipe coupler to join to the valve.
https://www.homedepot.com/p/Fernco-3...9-33/203310955
BTW, while you have the bottom open, can you see what tank heaters you have (pictures?) I am curious what Keystone is using. Also is there any insulation between the coroplast and tanks (4 season?)?
Also, where does the furnace duct that heats the underbelly come out at?
Maybe I should just open mine up to satisfy my curiosity, lol.
