TDS

[DYIguy]

I know zero is where it should be. I have a Spring fed well and the water varies, sometimes it' close to 400ppm, today its 110ppm, what my R/O is putting out it's at 9ppm- guess it's time to replace the cartridges- but I wonder when my well water is putting out water with tds this low, whether it's safe to use for changes or fill

I know there are other things the filter removes- but just wondering

 

[MadReefer]

I wouldn't use it as to me 9TDS. I see tank problems when I used 6TDS. Lots of algae plus cyano wich can become dinos.

 

[Mark_C]

Nope, nope, and nope.
0-1 tds then salt mix puts in everything you need.
I had a few blooms and couldn't figure it out.
Then realized I was filling occasionally from my home filtrations system (RODI).
But, my home system has a mineral cartridge at the end, brought me up to 10tds, even though good stuff in it (for human water at least).
Still caused probs.
As soon as my tds from my fish RODI system hits 2-3 they're replaced.
If I still have 2-3 after the change, I replace the membrane.
JMHO.