TDS

[sarimus]

Hi all
Question on TDS, out of my RO unit i have zero ppm in the water, but when I drop my tester into the aquarium I get 88 ppm. Only thing in the aquarium is the RO water, Caribsea life rock, Marco rock and Caribsea Aragonite sand.
I have not added salt or anything else. I thought it would still be zero.
Do you people know of anything that would make the TDS go up.

Thanks Maryanne

 

[sarimus]

I should add, it’s a 450 litre tank and it’s only half filled and the RO water has been in it about 5 days.

 

[Tangdora]

The RO mixing with the content of the live sand and rocks would have definitly added foreign solids that are now being picked up on your meter

 

[sarimus]

Hi thanks for the reply, so do I need to remove that water or do water changes until it starts showing zero

 

[EnterName]

Hi thanks for the reply, so do I need to remove that water or do water changes until it starts showing zero

No it's fine, I wouldn't worry about it.

Even letting RO/DI sit in a clean container will make it increase TDS over time as CO2 dissolves into the water and dust introduces all sorts of things that partially might dissolve.

 

[Randy Holmes-Farley Verified Community Expert]

TDS is not a thing to worry about except to gauge the performance of an ro/di. Seawater is tens of thousands of ppm tds. It is just a measure of total ions in the water.