TDS Issue Has Me Stumped

[Dan I]

Hey everyone! I am finally at the stage of adding water to my new build, but am running into an issue. I have cleaned my BRS RODI unit couple weeks ago in preparation of the new tank. Got new sediment and carbon filter and topped it off with some di resin I had. I replaced both my membranes last June 2019. In my previous location, my unit was outside that would get some sunlight. So, the issue I am running to is that my output TDS is ranging from 5-7 with an input of 3 TDS at 60psi. When I add my aquaboost pump to push 90psi, I get around 10-12 TDS.

All fittings are tight and no leaks anywhere. I have always got 0 TDS output in my previous locations, don't know what is happening now. Any input is appreciated! I do have a new bag of DI resin I can test it if needed.

 

[W1ngz]

The 3 tds in, is into what exactky? Into the unit? Into the resin?

 

[Fishy212]

Remember to flush out the new membrane !

 

[Sisterlimonpot]

More info please. Where are you testing TDS. and what are you using to test TDS? Would you happen to know if the membrane stayed wet?

 

[Dan I]

Remember to flush out the new membrane !

When I first got it, I flushed that bad boy out good. No issues when I used my unit since the move.

The 3 tds in, is into what exactky? Into the unit? Into the resin?

3 TDS before DI resin.

 

[Dan I]

More info please. Where are you testing TDS. and what are you using to test TDS? Would you happen to know if the membrane stayed wet?

Using new inline TDS meter and handheld TDS meter. Unit was probably not in use for around 2 months. I had the unit running at the moment for 50 minutes. Still showed no improvement in TDS which brought me to ask for help.

 

[Sisterlimonpot]

2 different devices to test TDS? have you calibrated the meters? Let's apply some troubleshooting measures to figure this out. I bet that if you were to test the TDS before the DI with the handheld you would get a higher reading than the inline. take the inline meter out and test the same water to see if both TDS meters have the same numbers.

 

[W1ngz]

IME resin that sits too long gives out or needs to produce a lot of water to flush it.

Same for unused new resin in a closed bag thats been unsealed.

 

[Dan I]

2 different devices to test TDS? have you calibrated the meters? Let's apply some troubleshooting measures to figure this out. I bet that if you were to test the TDS before the DI with the handheld you would get a higher reading than the inline. take the inline meter out and test the same water to see if both TDS meters have the same numbers.

Water before DI with handheld test at 28 TDS. Inline meter is testing 5 TDS before DI now.

 

[Dan I]

IME resin that sits too long gives out or needs to produce a lot of water to flush it.

Same for unused new resin in a closed bag thats been unsealed.

That is what I thought, bag was received on June 2019. Should I try the sealed bag I have?

 

[Sisterlimonpot]

Water before DI with handheld test at 28 TDS. Inline meter is testing 5 TDS before DI now.

There you go. Do you have any calibration fluid? if not you can use distilled water if available. not the ideal way, but you can calibrate to 0 with distilled.

 

[W1ngz]

That is what I thought, bag was received on June 2019. Should I try the sealed bag I have?

Yeah I'd toss any resin that isnt fresh, but first like above double checking the TDS readings woildnt be a bad idea, as well as giving the membrane a good 10 minute flush.

 

[Dan I]

There you go. Do you have any calibration fluid? if not you can use distilled water if available. not the ideal way, but you can calibrate to 0 with distilled.

No calibration fluid, but I do have Kirkland Bottled Water. Is that good enough?

Yeah I'd toss any resin that isnt fresh, but first like above double checking the TDS readings woildnt be a bad idea, as well as giving the membrane a good 10 minute flush.

I'll toss in the new bag and see if that fixes after troubleshooting with sisterlimonpot.

 

[Sisterlimonpot]

No calibration fluid, but I do have Kirkland Bottled Water. Is that good enough?

is that drinking water? If so, then no. You'll want something that has a known 0 TDS. Or if you trust that the inline meter is accurate you can calibrate to that. But then you're just guessing.

Although if that's the only option, at least you will have 2 meters reading the same info and you can at least tell if your DI is working.

 

[Dan I]

Okay, so I opened new bag of DI and noticed how much more blue the resin was compared to my old bag. Packed my di into the unit and flushed another 10-15 minutes. Now producing 0 TDS tested with inline and handheld meter. Thanks @Sisterlimonpot and @W1ngz ! Will do a test with callibration fluid to have a accurate readings.

 

[W1ngz]

Awesome, glad it's going.

Another thing you could do is pull the probes from the in-line T fittings. Remember to cut the water and depressurize the lines first. (Ask me how I learned that one... ) and test the water in a cup or jar with them manually, and compare to the handheld. That will tell you if they're close. Testing water in a cup will always read higher than in-line, just because of normal atmospheric contaminants and whatever even unseen might be contaminating the jar.