Back-flushing an RO membrane.

[seventhz]

How does one back-flush an RO membrane? I have an RO/DI unit that was given to me and I'm read that if it is recommended to flush the membrane on occasion but I can't seem to find instructions on how to do so and the person that gave me the unit doesn't remember how to. I'm pretty sure that the unit is setup to do such a service because it has a couple of valves on it for pressure regulation but I can't seem to figure it out though. Here's a picture of the unit that was given to me... can anyone please help? <IMG SRC="http://iamseventhz.tripod.com/gallery/pets/IMG_3541.JPG">

 

[redfishsc]

The back-flush on the unit I have (AquaFX) basically has a small valve that bypasses the restrictor on the waste-water output.


When you turn the valve, the wastewater start spewing HARD.


FWIW, Melev says on his site (where he sells his RO/DI) that the flush is pretty much a gimmick.


I have one, so I use it for 15-20 seconds, but I dunno if it does any good or not.

 

[seventhz]

Thank you for the input redfish. I fear that I need to replace the RO membrane anyways because I know that it had been in service for about 4 or 5 years before I got it and I've read that it's recommended to replace them about every 3 years anyways I just recently replaced both sediment filters and the primary DI cartridge along with installing a TDS meter and the meter is still reading an output of 30-50ppm so I know that something is foul and I have to assume that it's the RO membrane. Yippee! Let's spend more money that I don't have

 

[Duff Man]

Try seeing what your TDS is by disconnecting that top filter. The final filter actually adds stuff to the water for taste and is likely adding additional TDS.

 

[Duff Man]

Also, make sure that the black valve on the flow restrictor is perpendicular to the hose. This is your membrane flush and for the machine to work correctly, the valve must be positioned correctly.

 

[MplsMan]

do you have a in line TDS meter? if not i would recomend one.
here is what i have and love it, it will explain how to install one and there is also some info on how to install a flush kit.
http://www.bulkreefsupply.com/RO/DI...1:-IN-LINE-DUAL-TDS-MONITOR/product_info.html

 

[THE ROOK]

Duff is correct. Your unit has the flush valve already. When the unit has pressure just turn the valve parallel to the hose & most all water pressure will go out that line. That's your waste line. Close the valve ( perpendicular) & your clean water line will now have pressure.

Right now that valve is bleeding off most of the pressure. Need to turn it to get clean water.

Personally, for new membranes ( and Fliters), I'd check out Bulk Reef Supply. They now have a 150gpd membrane & matching restrictor for around $60.00 . That's a nice upgrade. Waiting all day for water just blows.