Advice on Calibrating a TDS Meter.

[SZHTTM]

Hello,

I was wondering if you could assist me by telling how you go about calibrating your TDS meter. I would like to know how often you perform this task and where you obtain the chemicals needed for the calibration procedure.

I have also heard that there are several different types of calibrations fluids. Is this true? What calibration fluid should be used to set your TDS meter for testing an RO/DI unit?

Thanks for all you help!!!!

[Sweettoothbear]

Depends on what type of T.D.S. meter you have. I have a Hanna... and use... Hi 70080-- 800 ppm solution.

It has a chart on the front... that tells you what to calibrate the meter... for what the solution is.... 800ppm

http://www.hannainst.com/downloads/instr/tds1.pdf



What type of meter do you have?

Solution is only 2 - 3 bucks a pack.

[SZHTTM]

Originally posted by Sweettoothbear
Depends on what type of T.D.S. meter you have.

What type of meter do you have?

Good question!!!! I know it is a Hanna, but I don't know the model number/name. I will check on that tonight and respond to your question.

Thanks for the help so far on this!!!

Good Luck and Have Fun;

[Sweettoothbear]

Sooooo..... whats the verdict Szhttm?

[SZHTTM]

I am so sorry!!!

I completely forgot to look at my meter to see what the model/name is.

I ran home and took pictures of my overflow for another thread here on RS and forgot about my meter.

I promise I will look at it tonight.

Thanks for following up with me!!!!

Good Luck and Have Fun!!!;

[Boomer]

I have also heard that there are several different types of calibrations fluids. Is this true?

Yes, there are basically 3 but there are others. They are KCl, NaCl and 442. 442 is the best choice but for us it doesn't much matter, which one you use.

Read this and let be know if you have any questions

http://www.hydroponicequipment.com/tdssolset.shtml

Finally, I would like to point something out. It is more or less a myth that you can measure TDS with a meter, as you can't.

It goes like this : Your sample water tests at 50 ppm and the meter is calibrated with NaCl. Now think about this........how could your sample have 50ppm NaCl, since when does tapwater have table salt in it ? What it means is this; **if you had a sample of your water that tested to 50 ppm and you compared it to a actual sample of water with 50 ppm NaCl, all it means is that the two samples conduct electricity the same, NOT that your sample has 50 ppm NaCl. All ions in water have a + or - charge. These charges add up to a higher level to conduct electricity. You know for example the salt water conducts electricty better than freshwater. These values can be crudely converted into a TDS value. The meter really is not measuring TDS but conductivity, the ability of water to conduct electricity. The more total dissolved solids the water has, the higher the conductivity. Conductivity is actually 1/ ohm's. This unit is often called Mho's ( ohm's spelled backwards) or Siemens ( named after the guy that discovered the unit of measurement).

Conductivity explained

http://www.wileywater.com/Contributor/Sample_2.htm

More

http://global.horiba.com/story_e/con...ctivity_03.htm

How we use it to measure seawater

http://www.aquariumfish.com/aquarium...id=124&search=

[Scooterman]

Poor ol Mho, he always gettig picked on!

You could test your water with 120vac, if it is pure you won't get shocked lol!

[BigReepher]

I had no idea that a TDS meter actually measures conductivity. Thanks for the links and info Boomer.

[SZHTTM]

Originally posted by Sweettoothbear
Sooooo..... whats the verdict Szhttm?

As luck would have it...I have the same (TDS 1) meter for the instruction you provided above in this thread. Is that cool or what!!!

Ok, where do you order your calibration fluid from?

Thanks for all your help on this!!!

Good Luck and Have Fun!!!;

[Sweettoothbear]

Fluid

http://www.marinedepot.com/md_viewIt...product=RO1353