A fluid pressure system (S) includes a flexible diaphragm bladder (172) located inside a pressure tank (164) installed within a fluid system such as well (168). In preferred aspects, the bladder (172) can be inflated by the introduction of air and is located within a flexible confining tube (198) for preventing over expansion of the bladder (172) and in the preferred form being of a cylindrical configuration and arranged concentrically around the bladder (172). The bladder (172) and the confining tube (198) are free floating in and without physical connection with the pressure tank (164) in preferred forms. The pressure tank (164) includes a flexible side wall (196) to allow folding or willing of the assembled fluid pressure system (S) in preferred forms.