Originally Posted by Montana Man
I hope I'm wrong but pls keep us posted.
So, a long-overdue update to my mystery leak; and I must first send out a giant THANK YOU to all those who offered up tips/tricks/troubleshooting/ideas to help point me in the right direction.
Turns out, my leak was coming from a small hole in the grey tank just above the outlet hole. It looks to me like something poked the tank at some point... my guess is at the point of manufacture because I just can't envision a scenario where the previous owner would have poked it in that particular location. In any case, I went out and bought some epoxy and sealed up the hole... no more leak.
As some of you pointed out, putting the CoroPlast up is a real bit$h. I ended up using my hydraulic jack to help hold up the material while I systematically installed the screws... holy freak, what a chore. Had my 13-year old help with handing me screws, interchanging sockets on my Dewalt drill (yes, inexplicably, there were TWO different screw hole sizes... and like I've said before, it is quite obvious that someone had taken the CoroPlast down before and then put it back up again... all kinds of holes drilled here and there).
In any case, a huge project and a bunch of learning-curve later, I've conquered the "Battle of the Bulge".