How reliable are cheap TDS pens to test RO/DI in the 0 - 3 TDS range? Hanna Pure Water Tester?

[Muffin87]

What is everyone here using to test the TDS of their RO/DI? Any tips or experiences concerning the reliability of cheap TDS pens?

Would you trust a cheap HM Digital TDS-3 Handheld TDS Meter? Plenty of positive reviews, but a reviewer pointed out:

I purchased this to verify my inline TDS meter was working properly. When I got it they were both off by 10 PPM. This was HMs response when asked about it: These meters are accurate within 2%, but have a range of 500ppm TDS, meaning 10ppm TDS is within that range of error.

The Hanna Pure Water Tester looks like a better alternative. Accuracy is ±2% (like the HM TDS-3), but a much lower range: 0.0 to 99.9 μS/cm range, i.e. 0-48 ppm range.

Do you need the extra accuracy of something like the hanna pure water tester, or a cheap TDS pen works just fine in your experience?

 

[Unregistered1]

That is the tds pen i have and it works great. To answer your would i trust a cheap tester...all are testers are cheap hobby grade. I actually have two of those and have verified off two and it always give me zero tds of my di. I checked them against distilled and same 0 tds.

 

[Muffin87]

That is the tds pen i have and it works great.

which one? the hanna PWT? or the HM TDS-3?

 

[Unregistered1]

Oh sorry i have the cheap HM TDS-3 well two of them becuase i thought i lost one...

 

[Unregistered1]

Its just for checking TDS...it is either zero or its not....mine i verify with distilled from time to time like i said above.

 

[Pistondog]

What is everyone here using to test the TDS of their RO/DI? Any tips or experiences concerning the reliability of cheap TDS pens?

Would you trust a cheap HM Digital TDS-3 Handheld TDS Meter? Plenty of positive reviews, but a reviewer pointed out:

The Hanna Pure Water Tester looks like a better alternative. Accuracy is ±2% (like the HM TDS-3), but a much lower range: 0.0 to 99.9 μS/cm range, i.e. 0-48 ppm range.

Do you need the extra accuracy of something like the hanna pure water tester, or a cheap TDS pen works just fine in your experience?

I have the brs rodi with integrated tds meter, output never exceeds 0.
If the ro membrane is working, shouldn't the tds be zero?
If it fails, won't the reading be > 10 tds?
I had a ruptured membrane on an Amazon rodi, tds 44.
Are there other failure modes that would give tds < 10.
If not, is the gross tds check sufficient?

 

[Unregistered1]

I have the brs rodi with integrated tds meter, output never exceeds 0.
If the ro membrane is working, shouldn't the tds be zero?
If it fails, won't the reading be > 10 tds?
I had a ruptured membrane on an Amazon rodi, tds 44.
Are there other failure modes that would give tds < 10.
If not, is the gross tds check sufficient?

No you will never get zero with the membrane alone...close but not zero tds....That comes from the Di Resin portion

 

[Unregistered1]

What is everyone here using to test the TDS of their RO/DI? Any tips or experiences concerning the reliability of cheap TDS pens?

Would you trust a cheap HM Digital TDS-3 Handheld TDS Meter? Plenty of positive reviews, but a reviewer pointed out:

The Hanna Pure Water Tester looks like a better alternative. Accuracy is ±2% (like the HM TDS-3), but a much lower range: 0.0 to 99.9 μS/cm range, i.e. 0-48 ppm range.

Do you need the extra accuracy of something like the hanna pure water tester, or a cheap TDS pen works just fine in your experience?

The TDS meter just lets you know that your Di "Deionized" filter resin of the rodi is taking the remaining tds " Total Disolved Soilds" out of the water making it zero TDS......the RO "reverse Osmosis" filter used for drinking water takes it down to 3 tds its varies on people system but not much. That DI water is the one that needs to be zero tds for the reef. Thats all you need a meter to tell you if its zero tds....if not then change your DI resin its exhausted

 

[Water Dog]

For handheld TDS meters, you want the TDS-3 meter. The “3“ signifies temperature compensation for greater accuracy in your measurement.

 

[monkeyCmonkeyDo]

I use the tds 3.
Waiting on new batteries now. I got the calibration fluid from a water supply online store.
D

 

[Unregistered1]

yes i have two they are good enough and cheap

 

[Unregistered1]

I use the tds 3.
Waiting on new batteries now. I got the calibration fluid from a water supply online store.
D

Batteries are hard to find locally but online...Though battery last like several years on mine

 

[monkeyCmonkeyDo]

Yup. Mines old. Lol. Luckily i took the battery out before it corroded. Nvr bought the new one. I ordered 357a from wallmart who shipped it from a vendor. Still waiting. Lol
D

 

[Water Dog]

What is everyone here using to test the TDS of their RO/DI? Any tips or experiences concerning the reliability of cheap TDS pens?

Would you trust a cheap HM Digital TDS-3 Handheld TDS Meter? Plenty of positive reviews, but a reviewer pointed out:

I would trust the TDS-3 handheld over the inline meters on RODI units. The inline meters on RODI units do not have the temperature compensation feature that the TDS-3 handhelds have.