fishman1234
New member
The water that is coming out of my RO unit is reading a 008 on the tds meter. The tap comes out @ 250. Does the RO water have to 100% be 000 reading on the tds?
Ro/di help!!!
- Thread starter fishman1234
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Capt_Cully
Active member
Do you have DI resin canisters after the RO unit?
fishman1234
New member
the resin is the last thing on and no it is not a new unit
fishman1234
New member
no..........???
fishman1234
New member
membrane is in there tight. the order goes sediment catcher, carbon, membrane then di.
DEEP BLUE SIX
New member
How many TDS meter lines do you have going in the whole system?
1 IN and 1 Out sections?
Try un plugging them and re inserting.
Also, try re setting the TDS meter screen it self, Purging out the unit, and letting some run out the good water line for awhile. See if it eventually starts going down... to 0.
Might happen to take a while. Several minutes. If not, then move on to checking at each point (if possible) with the meter. Or you may need to go to changing the filters out if nothing else. How old? Mine actually last a LONG time.
How old is the membrane?
As others have said, check the DI resin chamber too.- how long used? perhaps spent- leaching stuff back into water? If nothing else.. Try taking it off line. Save resin but empty chamber and run without DI temporarily. See what you get for a reading then.
You could be at a 1 or 2 and be ok I guess according to other people. But I've never settled for nothing less than 0 myself.
1 IN and 1 Out sections?
Try un plugging them and re inserting.
Also, try re setting the TDS meter screen it self, Purging out the unit, and letting some run out the good water line for awhile. See if it eventually starts going down... to 0.
Might happen to take a while. Several minutes. If not, then move on to checking at each point (if possible) with the meter. Or you may need to go to changing the filters out if nothing else. How old? Mine actually last a LONG time.
How old is the membrane?
As others have said, check the DI resin chamber too.- how long used? perhaps spent- leaching stuff back into water? If nothing else.. Try taking it off line. Save resin but empty chamber and run without DI temporarily. See what you get for a reading then.
You could be at a 1 or 2 and be ok I guess according to other people. But I've never settled for nothing less than 0 myself.
Last edited:
fishman1234
New member
All are new except for membrane
SkiFletch
New member
Take a sample of the water between the RO membrane and the DI resin. 250 is a lot of input and if you had a 100gpd membrane, 8ppm down from 250 would be pretty normal, just indicating a membrane in need of a little flush, and a saturated DI resin. If it's 8ppm before the DI (or maybe even something like 10) that would be my guess.
Post tds needs to be zero. The resins when exhuasted release ammonia, PO4 and other troublesome solids first as more highly charged ions bump them out. So even .01 tds from di could be a problem when it wouldn't be singnificant for just ro.
Test the membrane output with a tds meter. Typically, membranes have a rejction rate of 95% to 98%,so depending on your membrane's rating .I'd expect tds from the membrane to be 5 to 13 tds on an input of 250tds. If it's higher the resin will exhaust quickly.
Personlly, I use two di canisters with a tds meter in between them . When the output of the first one in line shows above 0, I change the resin in it and rotate it to second position. This insures 0 tds and eliminates the guesswork as to whether resin is exhausted; color changing is not especially helpful in gauging exhaustion ,ime. With two canisters and the tds meter in between I not only get 0 tds all the time but use teh resin more efficiently because I don't change it prematurely.
Also test after water is flowing for 30 seconds or so to get a fair reading to avoid reading the higher tds( tds creep) that can occur on start up. The in line meters are most effective when water is flowing.
Test the membrane output with a tds meter. Typically, membranes have a rejction rate of 95% to 98%,so depending on your membrane's rating .I'd expect tds from the membrane to be 5 to 13 tds on an input of 250tds. If it's higher the resin will exhaust quickly.
Personlly, I use two di canisters with a tds meter in between them . When the output of the first one in line shows above 0, I change the resin in it and rotate it to second position. This insures 0 tds and eliminates the guesswork as to whether resin is exhausted; color changing is not especially helpful in gauging exhaustion ,ime. With two canisters and the tds meter in between I not only get 0 tds all the time but use teh resin more efficiently because I don't change it prematurely.
Also test after water is flowing for 30 seconds or so to get a fair reading to avoid reading the higher tds( tds creep) that can occur on start up. The in line meters are most effective when water is flowing.
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