Ro/di ?

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JJ-MIK

Aquarium Advice FINatic
Joined
Jan 24, 2013
Messages
765
I have a 75gpd BRS rodi system. Just changed my filters and di resin. First 100 gallons were at 0 tds. Second 100 gallons is now showing 4 tds.. 3 weeks into the fikter changr.. My town water is 400 tds. Anyone know what's going on? I read that you want to change the filters when you start getting readings over 4.. It's only 3 weeks old..
 
Where are you taking your reading? If this is after coming out of the DI resin, you may be due for a resin change. My water supply is 465 tds, I get 3 tds coming out of my RO membrane, and I need to rotate DI resin cartridges about every 125-150 gallons.
This is where a dual in-line tds meter comes in very handy..... you hook the first meter between the RO membrane & DI canister so you can see the condition of your membrane before the water enters the DI, then one after the DI so you know when to change your resin.
 
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What do you mean rotate resin? I'm checking the water in the tub. And my di resin is new also. Color changing. And it hasn't changed colors yet
 
It's blue. Looks black right now. Like normal. Last time I changed it out . Half of it was brown
 
OK, then it should still be good. Run your RODI into a clean glass, rinse it a couple of times with the running RODI water (not out if the tub), and take a reading in that..... I'm guessing your using a handheld tds meter.
What kind of tub are you using, how new is it, and do you keep it covered? If the tub wasn't labeled "food safe", it could possibly be leaching a small amount of something back into the water if it's new.
As I mentioned before, one of these is a great investment for your system. Join in on one of the BRS group buys, and they are usually a couple $$ off:
Dual Inline TDS Meter DM-1 - HM Digital - Bulk Reef Supply
 
I've got a hand held meter. And it's a 100 g Rubbermaid tub from tractor supply. And I have plexiglass covering it . It's read 0 when I first gout the system. And after I changed the filters.
 
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