Tds in auto top off

[greenvrod06]

I just checked my tds levels and in the top off tank and its 300. I checked my rodi and it was 7 so whats going on

 

[greenvrod06]

i think i answered my own question, i used my old 20 gallon sump for the container with no lid, thats what imthinking.

 

[mlb75]

I'd say new filters are in order but yea it's probably coming from residue in the old sump and stuff that just lands in it from the air depending on how often that water is cycled through the reservoir. If the old sump was cleaned out though those numbers sound awfully high like a batch of non rodi water got added. What's the TDS of your tap water?

 

[greenvrod06]

tap water was 240. rodi out of the holding tank was 7. and top off water was 300, but i never cleaned out the sump completly, just rinsed it out.

 

[Ou8me2]

If you have any particles it can show high TDS if you are using a handheld TDS meter. Also if you are getting 7 TDS after the DI stage then you at least need a new DI as it should be 0 TDS.