Reliable TDS meter

Ryan Kraft · Nov 16, 2019

Hey guys, I have gone through 3 TDS meters in the last week. 2 were calibrated at factory and there is no access to calibrate yourself. The third has the adjustment screw. I have tested them all in calibration solution and all 3 were WAY off, and they were not reading the same as each other when I placed them in the solution together. I tried to manually calibrate the one but the closest I could get was about 100ppm off.
Does anyone have one that you trust?

Quietman · Nov 17, 2019

I'm not sure I'd use the word 'trust'. I use a TDS pen (and yes, it's measuring conductivity not actual TDS) from HM (about $25). It agrees largely with the TDS meters that came with my RODI (also HM equipment). But with TDS I'm not really looking for hyper-accurate readings. I'm looking for zero/non-zero (going into storage/sw bins), and order of magnitude readings (RO efficiency). I do check my planted tanks occassionally too, but again, that's order of magnitude. I did like the pen enough to get a pH/temp pen from HM as well if that means anything.

SyracuseMatt · Nov 17, 2019

I realize that this is 'non-responsive' but, what are you hoping to gain by having a super accurate TDS meter? Put another way, what decisions/actions are you planning to make/take based on the readings? Like Quietman, I basically use mine to determine if my RO/DI is working well (along with the meters in the unit itself). I don't think the meters are super accurate and would be reluctant to do anything to try to hit a particular number or make any significant changes to my tank based on the readings from the meter.

Matt

X-37B · Nov 17, 2019

Ryan Kraft said:
Hey guys, I have gone through 3 TDS meters in the last week. 2 were calibrated at factory and there is no access to calibrate yourself. The third has the adjustment screw. I have tested them all in calibration solution and all 3 were WAY off, and they were not reading the same as each other when I placed them in the solution together. I tried to manually calibrate the one but the closest I could get was about 100ppm off.
Does anyone have one that you trust?

I have had this one for several years. Very accurate and reasonably priced.

Ryan Kraft · Nov 17, 2019

SyracuseMatt said:
I realize that this is 'non-responsive' but, what are you hoping to gain by having a super accurate TDS meter? Put another way, what decisions/actions are you planning to make/take based on the readings? Like Quietman, I basically use mine to determine if my RO/DI is working well (along with the meters in the unit itself). I don't think the meters are super accurate and would be reluctant to do anything to try to hit a particular number or make any significant changes to my tank based on the readings from the meter.

Matt

I'm just looking to be sure that my RO/DI is accurate