TDS question...

Kimberely · Feb 28, 2018

The color changing resin in my RODI turned yellow after producing 30 gallons of water. I'm fairly certain it's due to high levels of dissolved co2 in my well water. My 3 line, inline tds meter tests 168 from the well, 4 after the membrane and 1 after the DI resin. Knowing so many people with successful reef tanks using unfiltered well water, I'm wondering if the DI resin is really necessary in my case? Unfiltered well water, no matter how clean, has to be higher than 4, right?

Kzguns · Feb 28, 2018

My well water is 250-400 tds! It helps if I flush the line first dropping tds in substantially. Make sure you’re buying good resin. The stuff that comes with your ro is probably not great stuff

Randy Holmes-Farley · Feb 28, 2018

Kimberely said:
Unfiltered well water, no matter how clean, has to be higher than 4, right?

Yes, but TDS is not what you are trying to remove, it is specific things like copper and other metals. The TDS might be 1000 ppm and be OK or 2 ppm and not be OK, depending on what exactly is in it.

Kimberely · Feb 28, 2018

Randy Holmes-Farley said:
Yes, but TDS is not what you are trying to remove, it is specific things like copper and other metals. The TDS might be 1000 ppm and be OK or 2 ppm and not be OK, depending on what exactly is in it.

My well is extremely clean. No copper, phosphate, etc. But the KH is really high. It's filtered through 500ft of limestone so from my tap it's 17dkh...hence the RODI.

NY_Caveman · Feb 28, 2018

Kimberely said:
My well is extremely clean. No copper, phosphate, etc. But the KH is really high. It's filtered through 500ft of limestone so from my tap it's 17dkh...hence the RODI.

Wow, 17 dKH! Must really dry out the skin showering.

My tap is 1 dKH. Always glad for that with my freshwater aquariums as it is easier to raise than lower.

Kimberely · Feb 28, 2018

It does dry the skin. It's terrible. Lol

Randy Holmes-Farley · Mar 1, 2018

Kimberely said:
My well is extremely clean. No copper, phosphate, etc. But the KH is really high. It's filtered through 500ft of limestone so from my tap it's 17dkh...hence the RODI.

Then it might be fine at 4 ppm TDS. If you want to post the well test results, we can check if there's anything we'd worry about.

Kimberely · Mar 1, 2018

Randy Holmes-Farley said:
Then it might be fine at 4 ppm TDS. If you want to post the well test results, we can check if there's anything we'd worry about.

I don't think I kept the result. And I can't remember what all they tested for, it was over 100 contaminants. I'll look for it and post it if I can find it.