Jay Posted November 3, 2007 Share Posted November 3, 2007 Hello: I got a new membrane today from Filter Direct. It is a 75 GPD membrane and looks to be working just fine I think. After 3 hours making water I am getting 5 tds after the membrane before the DI resin. I have not tested it after the resin but Im sure it is zero. Question is , is 5 TDS after a new membrane is installed ok? That is measured at the outlet of the membrane before it goes into the DI chambers. Thanks Jay Quote Link to comment Share on other sites More sharing options...
badguitarist Posted November 3, 2007 Share Posted November 3, 2007 the instruction manual that came with my tds meter said under 20 ppm is normal. my well water is at about 80 ppm and after running it through brand new membranes on my ro unit it was down to about 7ppm. hopefully that helps. Quote Link to comment Share on other sites More sharing options...
Jay Posted November 3, 2007 Author Share Posted November 3, 2007 I just hooked up the 2 DI resin chambers and its zero now after them but it seems like 5 is still high after the membrane. Jay Quote Link to comment Share on other sites More sharing options...
180Bob Posted November 3, 2007 Share Posted November 3, 2007 The last time I measured the RO output it was something like 3-5 ppm. Our tap water starts at about 60ppm. After the DI bed it drops to a reading of O ppm. So in my experience your 5 ppm does not sound surprising. It also depends on what is in the water to begin with. Quote Link to comment Share on other sites More sharing options...
spectra Posted November 3, 2007 Share Posted November 3, 2007 Jay, I asm in Vancouver also and water before the unit is almost 90 on the meter. After it filters through I get a reading of about 2 to 3 so I do not think you are in any danger. Quote Link to comment Share on other sites More sharing options...
Cobalt Posted November 4, 2007 Share Posted November 4, 2007 anyone have pressure gauges on their RO units? if so what is your inlet pressure reading, and where is your location? Quote Link to comment Share on other sites More sharing options...
Sol Posted November 6, 2007 Share Posted November 6, 2007 anyone have pressure gauges on their RO units? if so what is your inlet pressure reading' date=' and where is your location?[/quote'] I do. I get about 70 PSI at the filter. I'm in SW Portland. As I understand it "typical" household pressure is 60. To the original poster, my source water TDS is 30 and after RO is 2-3. So you're right on track. When it creeps past 10 or so, you should replace your membrane. Quote Link to comment Share on other sites More sharing options...
Jay Posted November 7, 2007 Author Share Posted November 7, 2007 Makes me wish I had a TDS meter on the outlet side of my membrane. Jay Quote Link to comment Share on other sites More sharing options...
impur Posted November 8, 2007 Share Posted November 8, 2007 It really all depends on the rejection rate of the membrane. Dow makes a 99% membrane. I would guess yours in 95%-97%. So 5ppm TDS after the membrane would make sense. Quote Link to comment Share on other sites More sharing options...
jayR Posted November 8, 2007 Share Posted November 8, 2007 Hey Jay I just hooked up my RO/DI (exactly like yours) & got a reading of 0 TDS, this is with a 1 yr old membrane, only using 1 Carbon Block. Local (Vancouver) Tap water reads 90 I did not test after membrane though, but reading 5 seems about right in your case. Quote Link to comment Share on other sites More sharing options...
Jay Posted November 8, 2007 Author Share Posted November 8, 2007 I have zero after the DI chambers .....Im good Thanks all Quote Link to comment Share on other sites More sharing options...
jayR Posted November 8, 2007 Share Posted November 8, 2007 Good to know. Jay: Does your RO/DI get the 75GPD of water? Mine is running very slow like 30-40GPD & mine is a 100GPD membrane. I think since the source is very cold & affecting its production rate? Does anyone else have this problem? Quote Link to comment Share on other sites More sharing options...
Guest Mbeef61 Posted November 10, 2007 Share Posted November 10, 2007 yes....i figure those ratings are optimal....my apt isnt exactly optimal...but my 50gpd does about 35....goes from 75ppm to 1ppm. Quote Link to comment Share on other sites More sharing options...
Jay Posted December 2, 2007 Author Share Posted December 2, 2007 Good to know. Jay: Does your RO/DI get the 75GPD of water? Mine is running very slow like 30-40GPD & mine is a 100GPD membrane. I think since the source is very cold & affecting its production rate? Does anyone else have this problem? Yea mine is about 50 gallons per day but Im ok with that. Jay Quote Link to comment Share on other sites More sharing options...
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