Check valve needed on 2 pipe jet pump?

Does a 2 pipe jet pump (100ft deep, 1.25" and 1" dia pipes) need a check valve on its discharge pipe, in between the pump and a pressure tank?
I suspect it would do more harm than good.

Thanks
Theodore

 

I am pretty sure you are right.

 

A few years ago my foot valve or piping on my 2 line jet starting leaking, in itself will only hold 15psi, so I put a check between the pump feed and the pressure switch, keeps my house/tank up to pressure but the pump drop lines pressure quickly drop to 12-15psi or so.

Been working flawless for a few years, however I'm in the middle of converting my dug well to a submersible since I know sooner then later ill probably loose my prime.

 

Thanks All.
Just replaced foot valve AND both hoses going down the well today.
I suspected the foot valve was leaky, but while pulling up the hoses, we found a pinhole leak in one about 40ft down! So opted to replace both just to be sure. Guy who was doing the bulk of the work with me got confused and asked about a check valve... which confused me too for a moment, hence my post. But it makes sense to avoid another check valve because it could end up needlessly triggering the pump to switch on/off rapidly.
Thank you again.
Theodore.