TDS Meter
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jaypainter24
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I always recommend a handheld over the inlines for both accuracy and ease of use/portability.
For a good middle of the road meter the HM Digital TDS3 is tops and for the best handheld I use and recommend the HM Digital COM-100. Its the only hobbysist grade meter that reads down to tenths and can be used and calibrated in three different modes for extreme low end accuracy like you want with DI water. the difference between 0 and 1 TDS is quite a bit when you think of it in conductivity/resistivity or microsiemens.
I have two of the dual inlines but only use them as a reference or rough guide, the COM-100 never agrees with what they say and I trust it more.
For a good middle of the road meter the HM Digital TDS3 is tops and for the best handheld I use and recommend the HM Digital COM-100. Its the only hobbysist grade meter that reads down to tenths and can be used and calibrated in three different modes for extreme low end accuracy like you want with DI water. the difference between 0 and 1 TDS is quite a bit when you think of it in conductivity/resistivity or microsiemens.
I have two of the dual inlines but only use them as a reference or rough guide, the COM-100 never agrees with what they say and I trust it more.
Mr. Tang
Active Member
Do these ever need adjustment?? I have an inline one on my RO/DI unit and it reads off the charts. But I now it's not right since I changed out ALL filters(including membrane) and DI resin.
So what do you think???
Sorry if this is off OT
So what do you think???
Sorry if this is off OT
They do require calibrations but the inline is a pain to calibrate and probably woundn't be accurate even then since they are not temperature compensated and need flow past the probe to work correctly, you can't just stick the probe in a glass of calibration solution.
I would get a COM-100 and forget about the inlines or use it like I do only as a guide, when its up I know something requires further attention.
I would get a COM-100 and forget about the inlines or use it like I do only as a guide, when its up I know something requires further attention.
Reefnjunkie
Acropora Junkie
+1 fot the one posted here-it tests the water coming in and going out.
You'll love the fact you bought a hand held, until you drop it in the water and watch the money you spent be waisted.
Inline for me the only way to go, especiially if you use a RO/DI unit!
Granted my water out of the faucet is about 12 on a TDS meter, unlike the water when I lived in Phoenix which is most likely 600-LOL
Ask AZrat-he works at a waterplant in Phoenix-MMMM Tasty!!!
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Inlines are not temperature compensated and can be off by quite a bit unless your air temperature and water temperature are exactly the same. They should be used as a guide only and a handheld used for accuracy. I have had a TDS 3 for over 10 years and a COM-100 for about 5 years with complete confidence in both.
Whichever handheld you get make sure it reads 0-999 TDS, has a resolution of 1, an accuracy no less than 2%+/- and is automatically temperature compensated. Those should be the minimum specs.
Many low end units are not temp compensated or have an accuracy of greater than 2% and are not worth the money. You can get a TDS3 for about $19-$25 and a COM-100 For $45-$59 most places. Its worth the extra for the COM-100.
Many low end units are not temp compensated or have an accuracy of greater than 2% and are not worth the money. You can get a TDS3 for about $19-$25 and a COM-100 For $45-$59 most places. Its worth the extra for the COM-100.
