picture shows up in the last post.
I'll assume there is some check valve upstream somewhere (probably in well). It is an old system I just got at a camp that got flooded by Isaac. New pump has primed and worked fine, but I want the csv in there since I'm sorta starting from scratch. May get a smaller tank at some point, but the old one is going strong, having survived Katrina, Isaac, and who knows what else. thanks