an electrolysis cell assembly of the filter press type having plastic frames and a membrane wherein the membrane is formed to fit between adjacent frames with one or more recesses provided on one or both of the adjacent frames together with sealing gasket means which are formed for effectively controlling electrode spacing and for retaining the membrane in position without membrane damage . the construction not only provides proper sealing and protection of the membrane during use , but also allows for the membrane to be removed , reactivated , and reused .