High tds readings

[mike r]

So after being out of the hobby for 3 years I’m gonna be setting up a fluval sea 13.5. I have a 5 stage ro system with 1 di 10in resin cartridge. All filters were just replaced and flushed. I’m having a issue with my tds after my di cartridge. My incoming tds is 335ppm, after the ro its 13ppm and after my di it’s 8ppm.
Now on my old tanks 3 years ago we were on city well water and I was to get zero tds no problem. Now we’re are on Lincoln pipestone rural water. So I’m thinking it’s gotta be something in the rural water that’s not being taken out. Anyone else on rural and have to do extra beyond a 5 stage?


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[Uncle99]

I get the same reading when the following happens
- the DI cartridge is not sealed perfectly
- the DI resin is exhausting
- you sample from a cup, instead of the bucket

[bertoni]

Is that 8 ppm measure from water straight from the filter? The TDS will rise over time. Also, it's possible that a fair amount of carbon dioxide is getting through the filter. You could try aerating a sample outside for a few hours, and measure the pH change (if any). That'd give some idea of the carbon dioxide content.

[mike r]

Ya it’s right after the di cartridge. I called Brs today again and I’m gonna try a valve after the di cartridge to reduce flow and increase contact time. It does seem to be flowing into my holding tank a lot faster than when I was on city well. Around 35 psi then and 55 psi now


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[bertoni]

Okay, maybe that will fix it. If not, I'd double-check the measurements and work from there.

[mike r]

Nope it didn’t work. Hmm yes I am testing right after the cartridge. I will try givein it a mixing a shot tomorrow


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