HELP* TDS meter tester question

[Aqua Amie]

Ok, so I'm not a newbie, but not a chemical engineer either...I got a new handheld COM 100 Water Quality Tester by HM digital, because I thought it would be pretty cool to test for a few things at once, then just bring the tester over to my other tanks and check those too. The problem is, after getting it in, and reading through the instructions in it's entirety, I have no idea how to get this thing to work right...I tried several different setting combos and still only get 2 lines when I put it in ANY water??? I'm a pretty smart cookie and all, but good grief, this was a little much :squigglemouth: Any advice would be helpful. I am trying to test my tanks as well as my RO water, so I know I may need to change the settings to go from one to the other, but so far, no settings have resulted in a reading of any sort?
Thanks in advance!

This is the meter I have:
http://www.tdsmeter.com/products/com100.html

 

[RBursek]

What does the digital read out say when you turn it on? You could also call where you bought it from.

 

[Aqua Amie]

When I turn it on, it says ppm 0.0 NaCl 79.8 F

I guess I could call, just thought I might get a quick answer here...maybe really simple something I'm missing...the temp is reading but not the tds or the elect. conduct.

Thanks for the quick reply!

 

[AZDesertRat]

You cannot test the TDS of your tanks with a TDS meter. The meter reads up to 1000 in low range and up to 10,000 by tens in high range. Fresh new saltwater is going to be somewhere over 32,000 so is way out of range.

The advantages of the COM-100 are its extreme low range, it reads in tenths of a part per million compared to almost all the others which read in ones or whole parts per million and above, some read by twos or tens even so it is much more sensitive. Another advantage is its portability, you can read the tap water, RO only, RO/DI, bottled water, vending machine, the neighbors, the LFS RO water, etc.

You will get two lines of information as you say, one is the TDS reading in ppm and the other is the temperature. It has three modes of calibration so the wording like NaCl may change depending on which mode you are in if you push the mode button.

You might ask your questions in the Spectrapure Sponsors Forum here on R2R, they are a HM Distributor and where I purchased my COM-100. I asked them once myself but its been so long now I don't even remember what mode they recommend you operate it in. Might be a good refresher for all of us!

One thing I will recommend, always rinse the meter in RO/DI after each use, cap the probe and put it away clean. If you have dipped it in saltwater give it a very good rinsing with RO/DI as it can ruin the probe.

 

[Aqua Amie]

You cannot test the TDS of your tanks with a TDS meter. The meter reads up to 1000 in low range and up to 10,000 by tens in high range. Fresh new saltwater is going to be somewhere over 32,000 so is way out of range.

The advantages of the COM-100 are its extreme low range, it reads in tenths of a part per million compared to almost all the others which read in ones or whole parts per million and above, some read by twos or tens even so it is much more sensitive. Another advantage is its portability, you can read the tap water, RO only, RO/DI, bottled water, vending machine, the neighbors, the LFS RO water, etc.

You will get two lines of information as you say, one is the TDS reading in ppm and the other is the temperature. It has three modes of calibration so the wording like NaCl may change depending on which mode you are in if you push the mode button.

You might ask your questions in the Spectrapure Sponsors Forum here on R2R, they are a HM Distributor and where I purchased my COM-100. I asked them once myself but its been so long now I don't even remember what mode they recommend you operate it in. Might be a good refresher for all of us!

One thing I will recommend, always rinse the meter in RO/DI after each use, cap the probe and put it away clean. If you have dipped it in saltwater give it a very good rinsing with RO/DI as it can ruin the probe.

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Thanks for the great info! It makes complete sense about measuring TDS in SW, it just didn't occur to me, since the applications with the unit specify for use in aquariums. It should, however read the conductivity? or would that also be out of range in the SW system....I also tried it in my RO water and tap, but still only got 2 lines...I also assumed---I know, I know, never assume---that since there was a NaCl setting, it would automatically take the SW range into consideration with the correct settings....

I will gladly take your suggestion and post this question in the Spectrapure forum, as they are sure to have the answers...thanks I did not think of that!

Thanks again!

 

[AZDesertRat]

You will only get two lines of information, TDS or conductivity depending on the mode you are opertating in and temperature in either F or C again depending on how you have it set up. So on your tap you should see something like 250.x TDS and 58 degrees F or whatever it is. on your RO only you should see a similar temperature but a 90-98% reduction in the TDS or something like 5.x to 10.x TDS

If you are looking to switch between KCL,442 and NaCl readings you will need to switch modes each time. I believe the meter is factory calibrated with NaCl so you would have to calibrate it with different solutions to be accurate in the other modes. I leave mine in the factory mode.