Allllllllrighty then, so while I was waiting for the polyurethane foam on my 3D background to cure this aft, I had a chance to start building the sump. Originally I was going to use a 50gal rubbermaid bin. It could have been done, but it presented a few issues that I didn't feel like dealing with:
1) making dividers for it would suck because it's a weird shape
2) it's 50 gallons total, but bows a LOT when filled with water, and has drain holes about 3/4" of the way up, where the handles are molded in, so it would only hold about 30gal.
3) Not space optimized for the room I have available.
Anyways, for $21 I bought a sheet of 3/4 spruce ply and slapped together a 70gal sump this afternoon. Sometime down the road I'll start actually putting the dividers and crap in it:
Epoxying inside:
Didn't take me long to find a use for the 50gal rubbermaid: