RODI rejection rate ???

R

ReefNut2010

Does RODI rejection rate increase when all filters are changed. I just changed all filters on my 6 stage unit and added a much needed TDS meter. Its reading 10ppm after membrane and 0ppm after DI resin filters. Rejection rate looks to be much higher !!
 
The term "rejection rate" applies only to the RO Membrane. It is calculated like this:
100% - (RO TDS/Feedwater TDS)

So in your case, the RO reads 10 ppm, and let's say that your feedwater is 200 ppm.

100% - (10/200)=
100% - (5%)=
95%

Prefilters (all the filters that touch the water before it reaches the RO membranes) don't remove TDS. That's don'e primarily by the RO membrane, and then the DI can be thought of as a polisher - it removes the small bit of dissolved solids that remain after the membrane.

Russ
 
Thanks buckeye. So I take it the new RO membrane is rejecting more water since its newer? i need a single TDS meter now for feed water. Just for curiositys' sake.
 
You can go with a handheld that you can use anywhere, or a single-probe inline like the SM1
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Russ
 
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