Flushing RO Membranes

[reefer madness1]

I just got a new membrane for my RO/DI unit. I seem to remember that these need to be flushed before you can use the water. Any one know how much/how long this needs to be?

 

[Anonymous]

I just changed mine and was wondering the same thing. I ended up running it for about 3 hours and decided that was enough. It continued to produce water at a slower-than-normal rate for the next few gallons, so perhaps I didn't do it enough...

 

[LCGoldman]

tagging along

 

[ChrisRD]

I thought I read a manufacturer or vendor recommendation that 5 gallons is sufficient... ...can't recall where I might have seen that though and I'm sure it depends on the membrane... :? I might be confusing it with the DI cartridges... ...not sure. I would start by asking the vendor you bought it from. If their answer didn't sound right I'd check the manufacturer.

Anyway, IIRC that's about all I put through my last membrane (about a 5 gallon bucket of product water) before starting to use it.

I'll move this over to the DIY forum (and keep a copy here as well) because I'm pretty sure a certain someone over there can help...

 

[Anonymous]

Yeah, you may want to throw away the first few gallons after changing the RO membrane. The 5 gallon rule is typical.

 

[Anonymous]

I am way past 5 gallons now, and it is still too slow. I wonder if I should try to re-seat it again. :?

 

[Anonymous]

If you want to reseat it, that's fine. Just make sure you don't rip the membrane, since it can be difficult to remove.

I doubt that it will improve the production rate by reseating, unless the rejection ratio is way off (leaking gasket, etc.). What is the GPH rating of the membrane, and how long did you wait for that 5 gal? Remember to give or take 100% (8O) when you read the GPH number....

 

[ChrisRD]

Also keep in mind that incoming water pressure and temperature will have a very significant effect on production rates...