RO membrane and Temperature

[vikubz]

Just wondering about the effects of low temp on RO membrane. I just got a 75 gpd Dow filmtec membrane to replace what appeared to be a faulty 50gpd filmtec.

I know that too warm water will ruin a membrane, but can too cold water have any negative effects, other than reducing the production rate of the membrane?

Thanks!

 

[AZDesertRat]

Cold water increases the waste flows too but doesn't hurt the membrane in any way unless you freeze it.
To get an idea of how temperature and pressure affect output look at the nice calculator Russ has put together on the Buckeye Field Supply Sponsors Forum.

 

[vikubz]

Tonight I checked the waste to product ratio and it is at 3:1. I have heard the target should be 4:1, and that not enough flow can lead to the membrane clogging with minerals and such.

Is 3:1 low enough to be worried about? And if so, will a flush kit take care of it?

 

[AZDesertRat]

3:1 will be OK. Check it again in summer time when water temps are normally higher. If its lower still then adjust it to 4:1. If your water temps vary a lot over the seasons you might want to look at either and adjustable flow restrictor or having two inexpensive capillary type restrictors that you can swap out with the change of seasons/temps for best efficiency.