BRS Dual TDS meter ?
 

I have a BRS RO/DI system, with a dual TDS meter. My TDS reading IN is always 0, which does not seem right to me. Was I supposed to calibrate it before I installed it or something, what gives?

Where do you have it attached? Are you measuring it with the water flowing? It generally takes a few minuets before it will read correctly. You might want to check your installation again, if I remember the probe inside the tee has to be positioned.

If yours is like mine that I bought from BRS, it was already installed when it came.
The TDS IN is reading the TDS of the water after it has gone through all the filters,
( carbon, sediment, ro ) and just before it goes into the DI unit.
Mine usually reads about 1.
If yours reads 0, that means the RO side is stripping all the TDS out before it hits the DI side, which can be a good thing. Makes the DI resin last a long time.

Also, they have great product support, call them if you have a problem.

I just got my BRS 6 stage filter with cholormines .. The Dual TDS meeting shows 15 on the in and 0 on the out. Not sure why my TDS after the RO is so high???

I tested my tap water (flowing) and it has 255 TDS. That would put me at 94% reduction.. is that normal?

My tap water is usually between 35 and 50, so that might explain my lower TDS after the RO and before the DI unit.

It all depends on your tap water TDS.

Membrane performance varies slightly and the lower volume/rate membranes typically have a better rejection rate than the faster producing ones such as 150s. Water pressure & temperature will also affect performance. My 75 gpd membrane gets the RO down to 1 and even 0 with tap source TDS in the 210 to 230 range. Every time I start up the system I monitor the IN TDS and it initially starts at just under 200, taking a good minute to slowly get down to 1. After running for about 10 minutes it generally gets down to 0. This is one reason I produce a few gallons of RO water for drinking purposes before switching to DI water production. I'm still on the same membrane & DI media after more than two years and thousands of gallons throughput. Something else I've noticed is that every time after I do a manual flush, there's a slight peak in RO TDS once I go back to normal operation. So be aware that although frequent flushing may be good for the membrane and speed up production, it will also make your DI work just a little harder and use it up faster.

If tds out of di says 0, then I can be certain there are no chloromines?

I think chloromine could make it through the membrane, thats why you need a good carbon block (made for chloromines). It should be absorbed in the DI but will shorten the life.

Thanks for all of the input. Should I be reading my meter with the water flowing or sitting in the line?

Water must be flowing to get an accurate reading. Also, let your unit run for a little while before checking.

Here are the specs for our membranes:

http://i224.photobucket.com/albums/d...orySpecs-1.jpg

Russ

Chloramines are split back into chlorine and ammonia by the carbon block. Much or the ammonia makes its way past the membrane and is captured by the DI resin.

Russ

I got one from BRS and it came NOT calibrated. Said it would so I was running everywhere trying to figure out my filter situation, so I bought all new filters and other stuff when really everything was fine. Called BRS and they said call HM digital. HM digital gave me the run around and said I need to order calibration fluid. They said how do you KNOW it was not calibrated? Well because I tested the water with 3 different testers after I figured out it was your meter. Still they want me to buy the calibration fluid before I send it in to them. Crazy...

My bad quoting the 150 as lower rejection rate. Out of curiosity though, is the 150 on your chart a single membrane or two 75s in series? Thanks.

Single membrane - same size as the others.

Russ