An RO membrane flush valve is a great addition to tankless RO systems, saltwater/reef aquarium systems, or even drinking water systems with storage tanks. The purpose of a flush valve is to eliminate high TDS water at system startup, due to TDS creep. TDS creep is a phenomena where high TDS water trapped between RO membrane sheets, passes through the RO membrane by diffusion.
Flushing the membrane for 15-30 seconds creates a large increase in water flow along the membrane surface, washing away salts and other contaminants on the membrane surface. This improves membrane performance, reduces RO water TDS, and extends membrane life.
We recommend a weekly membrane flush for drinking water systems with storage tanks to keep the membrane clean. For saltwater/reef aquariums, membrane flush before each use will significantly extend the life of mixed bed ion exchange filters installed downstream of the RO membrane.
See the attached for a detailed description of membrane flush valve installation and operation.