Lab scale Forward osmosis (FO) self-built system that provides fast and accurate performance data with minimal amounts of membrane. It is designed to be used for both flat-sheet and hollow fiber membranes under no/low (up to 2 bars) hydraulic pressure. The operating conditions and fluid dynamics can be varied over broad ranges. It mains features are various cross flow membrane cell units, feed and draw solution tanks, peristaltic pumps along with flow meter, a conductivity and a balance for automatic data recording.