Top tds meter to buy?

Notsolostfish

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100$ budget. Whats a good tds meter to buy? For absolute accuracy?
 

Sean Clark

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This is out of the budget but...
I use this controller from HM Digital:

CIC-152-N / CIC-152-4 – HM Digital


hmdigital.com
hmdigital.com
It has two relay outlets for high and low limits that you can wire into an Apex breakout box or other controllers to automate flushing or alert you to change your DI. I like it, but it is a bit more involved then some other solutions like a SpectraPure unit with an automatic controller.
 

Woodyman

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Like accurary and good tds meter? Why they dont exist?

As the sensitivity and resolution of the equipment increases so does the cost.

The HM digitals are sufficient for hobbyist use, both of the 2 above as well as the this one all have a stated accuracy of +/-2%, the resolution is different but so is the cost.

The one @Sean Clark posted has a resolution of 0.1 (up to 1000TDS), where the one posted by @KStatefan has a resolution of 0.1 (up to 99.9TDS).

Another widely used HM branded one is this one:

However the resolution on it is only 1ppm.
 

Woodyman

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As the sensitivity and resolution of the equipment increases so does the cost.

The HM digitals are sufficient for hobbyist use, both of the 2 above as well as the this one all have a stated accuracy of +/-2%, the resolution is different but so is the cost.

The one @Sean Clark posted has a resolution of 0.1 (up to 1000TDS), where the one posted by @KStatefan has a resolution of 0.1 (up to 99.9TDS).

Another widely used HM branded one is this one:

However the resolution on it is only 1ppm.

So ~$50 for the DM-2

Then ~$90 for the LDM-1000R

And ~$300+ for the CIC-152
 

Mike konesky

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Hanna HI98301 ($55) if just tds, HI98130 ($160) if you would like to test ph as well.
 

LeftyReefer

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A TRM-1 (triple in-line) TDS monitor is great for monitoring RO/DI systems.
Sensor 1 = incoming source TDS
Sensor 2 = Post RO membrane (monitors RO membrane performance)
Sensor 3 = Post DI stage (monitors DI resin performance)

$35 with free shipping at Amazon currently.

then if you want, you can also get a hand-held TDS meter for spot checking and verification.
 

Randy Holmes-Farley

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Why its irrevelant?

Because any tds meter properly reads 0 ppm tds (if it doesn’t read zero in air, it is broken).

Then imagine you are watching your RO/di effluent for a rise in tds from 0 ppm to know when to change it.

Does it make ANY difference to the need to replace it if it properly reads 2 ppm, or is off by a whopping 50% and mistakenly reports that as 1 ppm or 3 ppm? I don’t think so. As soon as you see a detectable rise it’s time to change it.

No one needs to know that the effluent tds is 2.00 ppm and not 2.10 ppm tds. :)
 
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Notsolostfish

Notsolostfish

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Because any tds meter properly reads 0 ppm tds (if it doesn’t read zero in air, it is broken).

Then imagine you are watching your RO/di effluent for a rise in tds from 0 ppm to know when to change it.

Does it make ANY difference to the need to replace it if it properly reads 2 ppm, or is off by a whopping 50% and mistakenly reports that as 1 ppm or 3 ppm? I don’t think so. As soon as you see a detectable rise it’s time to change it.

No one needs to know that the effluent tds is 2.00 ppm and not 2.10 ppm tds. :)

My tds is in the brute trash barrel for mixing is 2ppm. It comes 0 tds from the main unit. But its 2ppm in the trash barrel why is that?
 

LeftyReefer

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My tds is in the brute trash barrel for mixing is 2ppm. It comes 0 tds from the main unit. But its 2ppm in the trash barrel why is that?
any residual salt in the barrel from the last time you mixed SW?

It does not take much salt to add TDS back to 0 TDS water.
 

Randy Holmes-Farley

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My tds is in the brute trash barrel for mixing is 2ppm. It comes 0 tds from the main unit. But its 2ppm in the trash barrel why is that?

CO2 from the air alone can add a ppm or so. Tiny traces of salty dust can easily add more.
 

ScubaFish802

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Is the brute can food grade or similar? If not I wonder if it's possible there is something leeching from the plastic. Only throwing this out there as I've seen another thread before on brute cans and tds
 

Sean Clark

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The rodi is starving for anything that it can get its little molecules on. It will pull stuff from the air and the tds will increase.

I only use my tds controller for its built in relays that allow me to automate the system and alert to me when maintenance is required, not for its accuracy.
 
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