TDS the same before and after DI


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Hi guys,

So I recently replaced all my filters in my RODI unit they were all pretty old.
With the new filters and DI I’m still not getting 0 tds. Tested last night before the DI TDS is 0.03 and after DI also 0.03?
Do I have crap resin? Surely even crap resin should cope with 0.03 to get it to 0.

Any ideas? Thanks
 

viper357

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First time I've ever seen TDS measured to decimal places. I'm happy if my TDS is less than 10. I really don't think you should be concerned with this. When your TDS doesn't drop from higher numbers like 30 to 0 after the DI then it's time to replace it. Worrying about 0.03 is a bit overkill, you're going to stress yourself out, lol.
 
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So basically your reading is 3ppm before and after.
Have you ever calibrated the TDS Meter?
It could be that the meter is not calibrated or it could be that the resin is starting to saturate, you mention that you replaced the filters but did you replace the resin?
Also did you flush the RO unit before testing the water?
At the end of the day as Viper mentioned though 3 is still not bad at all
 
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So basically your reading is 3ppm before and after.
Have you ever calibrated the TDS Meter?
It could be that the meter is not calibrated or it could be that the resin is starting to saturate, you mention that you replaced the filters but did you replace the resin?
Also did you flush the RO unit before testing the water?
At the end of the day as Viper mentioned though 3 is still not bad at all
Replaced everything. Repacked DI because I thought I might have channeling. I’ve probably made 100l since I replaced it all. Ran about 15-20 minutes before I tested after repacking DI. So might just be the tds meter.
How do I go about calibrating it?
 
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