Dave, No complaints here! I am a believer in pressure tanks to level out pressure demands. They aren't that expensive and in a protected location should last a long time. As far as space considerations go, I can build a stout shelf if I want and get it up out of the way but don't think it is a sure thing that the effort will be required.

As my first training was electronics (even ahead of physics) I tend to think of a bladder tank as a capacitor and flow resistance like electrical resistance and it is all pretty simple. Pumps are just current and voltage sources with certain transter characteristics. Even water hammer "computes" but is perhaps a tad convoluted in an eletrical analogy.

I do like the suggestion to use a shallow well pump but the other stuff is outside of my experience. I don't know what its innards would look like and it would take some convincing (that hasn't been forthcoming) before I would adopt any valve to replace a bladder tank.

I put small pressure tanks in my RV's to reduce short cycling of the 12VDC pressure pump. Make an amazing improvement to run times as sell as reducing the variabillity in pressure when the pump is running.

[img]/forums/images/icons/smile.gif[/img] Pat [img]/forums/images/icons/smile.gif[/img]