New RO/DI

You probably have a flow restrictor or you would not get any treated water at all. What system do you have? Some restrictors are internal to the waste line and not obvious.
What is your water temperature and water pressure at the unit?

 

Yea I found it was a 450 ml flow restrictor on a 100gpd system.
It was purchased from purewaterclub.com. The temp is a bit colder than it should be at 56-62 degrees depending on time of day. And pressure is right around 50 psi. Would the smaller restrictor cause too much waste water?

 

I think you need a 750 for a 100 GPD system. I hope like heck they did not sell you a 100 GPD Dow Filmtec membrane, they are the worst possible choice since they are only 90% rejection ves 96-98% for the 75 GPD. If its a GE membrane its OK in the 100 size since its actually the same as a Dow 75.

If it were me I would get the capillary tube restrictor and trim it yourself so you know its correct and not just ballpark.

At 56 degrees and 50 psi you should be getting about 67 GPD out of the unit if it has the correct 4:1 waste ratio.
http://www.buckeyefieldsupply.com/calc.asp

 

No, it is just a no name "Made in the US" RO Membrane. Which I am sure is crap. Should I just replace the membrane right off the bat? Also we have a source here that is near 100 PSI unregulated from the street. Should I move the unit to that location? What would having an undersized flow restrictor do to the unit?

Thanks again!

Also after using that Calculator provided with new specs from the afternoon heat, I should be getting 4.04 GPH but am actually getting about .75 GPH so something is definitely wrong.

 

Before you buy anything, stick a 1/4" ball valve on the waste line and choke it down to approx 4:1 waste ratio and see what that does to your production, it may just need the correct restrictor.

At the same time, use your TDS meter and monitor the TDS readings from the tap water, RO only water, RO/DI water and the waste stream. If the waste is close to 4:1 your waste TDS should be 20-25% higher than your tap water TDS. If the membrane is functioning correctly your rejection rate should be in the 98% range. Of course the RO/DI TDS should be 0 at least for a little while.

Higher pressure will not only give you more GPD but it will also improve the rejection rate or removal efficiency dramatically. I run my RO booster at 100 psi and get 120+ GPD at 99.35% rejection rate out of a 75 GPD membrane.

 

That did the trick, the ball valve that is. Worked perfectly to make us a 4:1 ratio. Any reason I couldn't use that ball valve permentaly? I figure it's 6 bucks plus 6 more shipping I don't have to pay since it is adjusted to an exact 1 gallon pure to 4 gallons waste. Thanks again!

 

Its hard to fine tune a ball valve, get the capillary tube restrictor for $5 and take the few minutes it takes to trim the length so you don't have to fiddle with a ball valve. All it takes is one bump of the valve and its out of whack.