Stored 0 TDS RODI in a Seachem Jug outside. Water has a smell and 3 TDS. Why?

[rdriggett]

Hi all! I have a BRS 7 stage RODI with a booster pump that cranks out 0 TDS water into a 55G food grade water storage barrel outside. I then pump it into 5x 5G SeaChem jugs and store it under a tarp until that weeks use. I went to do a WC on my reef and the water had a noticeable plastic smell. It also tests @ 3 TDS. I'm going to dump this water and pump out fresh. My RODI output and my 55G storage barrel both test @ 0 TDS.
My question is: How do I know if these less than 1 year old seachem jugs are safe to use?

Edit: I rinsed and refilled the jugs with barrel water and it’s back to 0 TDS. Will it creep up again?

 

[popper]

I did a similar test at one of those shop that sells water using two TDS reader.

I used my dirty cup and it read 10. The shop keeper gave me a new clean cup and it tested 0.

I did my own test with my rodi. Sure enough, the dirty cup was the culprit.

 

[Srt4eric]

Unless your container is completely clean it will read something. Even if the water sits outside for a bit and it gets a little dust or pollen in it, there something dissolved in there.

 

[JVU]

If you made saltwater in the jug, then used the saltwater up, briefly rinsed, then refilled with RO/DI water it could easily measure 3 TDS and not be a problem. Recall that saltwater has a very high TDS, like 35,000. So if you rinsed in a way that diluted it 1 to 10,000 you’d still have TDS of 3. Not sure if that scenario applies.

As far as the plastic smell, I’m not sure. If you wash it thoroughly and empty it, and the smell is still there, it’s likely from the plastic. Plastic smell is from volatile chemicals, probably wouldn’t show up as TDS anyway. So maybe they are unrelated findings.