RO/DI Storage?

[NanaReefer]

I fill my 32g Brute up and test for TDS about every hour. End of filling I get 0 TDS.
Half way to empty I'm getting a reading of 001 at 3/4 I'm getting 002.
What's going on and is it bad to use this water?


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[mfinn]

There might be a little residue from manufacturing, or cleaning.
I've seen this issue pop up from time to time.
Have you mixed saltwater in this container?

 

[mfinn]

I cleaned out one of my salt mixing barrels (that I'd used for several years) as best as I could.
I filled it with ro/di for a friend whose ro/di unit broke.
When they came to pick up the water I grabbed my hand held TDS and stuck it in the barrel and it read 12TDS. I was shocked and embarrassed. I told them that I had good ro/di water and that it was 0, then that happened.
Then the guy asked me what this barrel was used for normally and I told him it was a salt mixing barrel and that when I realized that it picked some TDS from a tiny bit of salt residue.

 

[NanaReefer]

I cleaned it out very well with vinegar before ever using. It has had nothing but RO/DI water in it. I'm thinking it's just picking up residue from my mixing pump ( face palm ) which I use to mix salt & transfer water to my ATO-oops! Dang these meters are sensitive!

 

[dnjan]

I cleaned it out very well with vinegar before ever using. It has had nothing but RO/DI water in it. I'm thinking it's just picking up residue from my mixing pump ( face palm ) which I use to mix salt & transfer water to my ATO-oops! Dang these meters are sensitive!

Or you could just be having CO2 from the air dissolving in the water, which will increase conductivity and show up as an increase with a TDS probe.