Tighten the top turn knob until you get a drip....then a tiny bit more and then you will have a small flow. That probably is your point of maximum effectiveness in a low pressure situation. Time how long it takes to make a quart of good water. Then see how much waste water is generated in that same time. Play with it until the ratio is 3:1 and you are a "Green". This is how to set the proper back pressure for your system. THE E - Z Flush Flow Restrictor acts to put back pressure on the R.O membrane.Flushing of the membrane: Make sure the flow restrictor handle is in the correct position for normal operations. Flush once a month for 10-15 minutes. for normal water. High Calcium...well calcium cakes everything...membranes are no exception....high TDS....some customers have 1800...flush early and often. Low PSI...early and often. Sea water is at least 18,000 TDS, it takes 700 PSI to pass the membrane and they get cleaned once a week.