Your tank is 5 feet down? That should be illegal to install a tank without access covers. The exit baffle in my tank was made of concrete & it disintegrated over time. I'm glad I dug up the exit side of the tank to fix this problem. The seepage pit should have an aerator as explained in this website: http://www.doityourself.com/forum/wells-sump-pumps-septic-sewage-systems/4467...