30 TDS Need some input

The flow restrictor was not sized correctly and you have only been getting about a 1:1 waste ratio (not rejection rate) so the membrane is plugged and shot. You need a minimum of 3:1 waste to permeate and 4:1 is recommended.

Your rejection rate (removal efficiency) is only 84.8% which is way below the recommended 96-98%. No wonder your DI is exhausted, it has been doing most of the work.

With a new RO membrane you should see a RO only TDS of about 5 so the DI will last and last. With the Spectrapure membrane it will probably be a lot lower than 5 actually, my tap TDS is 600+ and I'm seeing a RO only TDS of between 4 and 5 myself.

With 57 psi and 69 degree wate rand a TDS of 278 you should see almost exactly 75 GPD out of a 75-90 GPD RO membrane and at 98% rejection.

If you get a new membrane make sure you get the $4.99 capillary tube flow restrictor too and take the time to trim it correctly once the system is flushed initially. Its easy and takes only about 5 minutes one time.

 

Thanks AZDesertRat, I have everything on order, Thanks for the link on the membrane! K+

 

I got a TDS meter in the mail today. AZDesertRat comment as needed. Tap was 156, RO was 8 and DI 1.

I have new filters as of last week.. I got them from Filter Direct. Not sure of the micron size. I was surprised at the tap readings, thought they would have been more.

 

First make sure you are using a squeaky clean clear glass drinking water glass, washed by hand in very hot water, not a dishwasher which can leave soap residue, water spots or antispotting films.
Make sure you triple rinse both the glass and the meter between each use so the readings are correct.

If they are still 156, 8 and 1 it could be better. Thats a RO rejection rate or removal efficiency of only 94.8% which should be 96-98% or higher. The DI should read 0 if its new, at least for a little while.
DI must be packed tightly with no voids or gaps so all resin and water come into contact with each other. If its a horizontal holow tube mounted on top, take it off and mount it vertically beside the standard 10" canisters so it fills from the bottom and exits the top for best performance.