RO/DI Question

[Snookin]

I just bought a used RO/DI unit. It came with a 75gpd RO membrane and a 800 RO flow restrictor. Is this a proper fit? From the research I have done a 550 restrictor is the best fit.
What is the difference between a 800 and a 550 flow restrictor?

 

[AZDesertRat]

The 800 will put you at about 4:1 waste ratio which is ideal for best membrane life and system performance. The 550 is more for a 50 GPD membrane.

Personally I would toss the fixed restrictor and get the much better capilary tube style restrictor you yourself adjsut to fit your exact water conditions. Fixed restrictors are only ballpark close so can be significantly off depending on your water pressure, temperature and tap TDS. The capillary tube is trimmed to fit your exact conditions by you so is precise and only $4-$6 at places like Spectrapure, Buckeye Field Supply and PurelyH2o.