Sump tank repair + Protein skimmer help

[PittsburghAqua]

Recently I was able to get my hands on a fairly large 20g sump tank and protein skimmer for dirt cheap. The reason, though, it was dirt cheap is for the fact that it only has the skimmer, and the sump tank is cracked.

http://img.photobucket.com/albums/v244/megans_true_love/IMAG0017_zps09500bf7.jpg

http://img.photobucket.com/albums/v244/megans_true_love/IMAG0018_zps0b2e0dd0.jpg

What can/should I use to fix the crack in the sump? And what do I need to get the protein skimmer working?

I am also confused by the elbow piece I show in the last photo. How do I go about connecting it up? I'm assuming the return to the tank is the other end?

http://img.photobucket.com/albums/v244/megans_true_love/IMAG0019_zpsf8788886.jpg

http://img.photobucket.com/albums/v244/megans_true_love/IMAG0020_zps171ecda4.jpg

Thanks for reading this everyone!!!!

[PittsburghAqua]

Update:

finally was able to determine that JB Weld, once fully cured, should be safe. I have sealed the cracks and will test with saltwater once it's fully cured.

So I just don't know about the protein skimmer and sump setup....