Capillary Flow Restrictor for Reverse Osmosis System - 420 mil

420 Mil Capillary Tube Flow Restrictor with 1/4" Quick Connect Fittings A capillary flow restrictor is used to regulate the drain water of a reverse osmosis system. Too much water running to the drain is a waste of water, and too little water running to the drain will cause the membrane to deliver lower water quality and dramatically impact membrane life. If you have clean, soft water you can use the smaller flow restrictor, but if you have harder water with no pre-treatment, by all means use the LARGER flow restrictor for increased membrane life. This Capillary Flow Restrictor is typically used for a 50 GPD Membrane. Follow this guide when choosing the proper flow restrictor: Membrane Size - GPD Drain Flow Ml 25 GPD 150 to 250 35 GPD 250 to 350 50 GPD 350 to 420 75 GPD 525 to 800 100 GPD 800