Water Conductivity can this be right?

[Astolfo]

I have a Neptune controller with a few probes, but I can figure out if the Conductivity probe is properly calibrated. I get a .97 is this possible? just does not looks right...
Also how does it relate to TDS?
thanks
Astolfo

[T_om]

I do not know of any quality meter that cannot be calibrated. Usually by using a test solution. My trusty Myron-L has worked for years and years.

Tom

[Astolfo]

I calibrated it 3 time it is a neptune probe.

[DiscusOnly]

What does it read in the calibration solution? Are you using the 447 S/cm solution?

Van

[Astolfo]

I am using a 3.9 mS/cm and the controller is set to medium as indicated in the manual

[DiscusOnly]

Is this for the Apex with PM2?

[Astolfo]

yes

[DiscusOnly]

Is the temp probe configured? Is there a temp probe attached to the PM2 or are you using the temp from the base unit? According to their manual, the temperature compensation must be set to 0.0 if there are not temp probe attached to the PM2.

To further clarify. You can not use the temp reading from the base unit for temp compensation of the PM2. If no probe is attached to PM2, you have to set it to 0.0

[Astolfo]

temp is set to 0.0 as indicated...
it is pretty wired
I know i calibrated this thing right. and regular water should be around 200mS/cm or a bit less if I recall correctly.
I emailed Paul and see if he gets back to me.

[Astolfo]

there is a spec range unit error in the manual. you need either 3.9 solution (Very hard to find I tried 6 different large companies) and set scale at 3.9 and medium , or 447 solution and 4.12 scale.
so the ColeParmer Tech (recommended by Paul @ Neptune) gave me the wrong equivalent solution.
I am getting now the 447 (much more easier to find) and will post the results.

It is frustrating that I had the probe for over a month trying to calibrate based on bad information from Neptune and no wander it did not work.
Life is a daring adventure or nothing

[muran90]

What usefull information on water quality can be applied to the planted discus tank by using an apex conductivity probe?

[Cosmo]

From the reading I've done, conductdivity is greatly more relevant to a high saline solution, or, a salt water tank.

I am not familiar with the neptune meter, but my Hanna meter will read both conductivity and TDS. Although it is adjustable, the factory default is a multiplier of 2. In other words, if the meter reads 100 TDS switching it to conductivity mode it will read 200. I have not researched whether or not 2 is the correct multiplier, and, since I am primarily concerned with TDS, I leave it set on the factory default and only use the meter in TDS mode which reads the ppm instead of conductivity.

I suspect it would be safe to assume that if your Neptune is reading a conductivity of 447 then your ppm (TDS) would be 224

[100fuegos]

What they really do is read the conductivity and thenn they "guess" the TDS. There is no way a simple devise like these can figure out how many ppm are in your tank. That is why some use the X2 to "guess" the ppm and others use a different multiplier.


From the reading I've done, conductdivity is greatly more relevant to a high saline solution, or, a salt water tank.

I am not familiar with the neptune meter, but my Hanna meter will read both conductivity and TDS. Although it is adjustable, the factory default is a multiplier of 2. In other words, if the meter reads 100 TDS switching it to conductivity mode it will read 200. I have not researched whether or not 2 is the correct multiplier, and, since I am primarily concerned with TDS, I leave it set on the factory default and only use the meter in TDS mode which reads the ppm instead of conductivity.

I suspect it would be safe to assume that if your Neptune is reading a conductivity of 447 then your ppm (TDS) would be 224

[Cosmo]

Could be, don't know to be honest. How are you sure it's not the other way around - easier to measure the electrical conductivity of the water? Conductivity seems to have no relevance to me in a freshwater aquarium and the TDS serves as a reference point - whether it's calculated or guessed.

Interesting point :)

[DJW]

There was a thread about this a while back... apparently all these meters do is measure conductivity, but the TDS meters use an internal conversion to express it in TDS, and some manufacturers use 0.5 and some use more like 0.58. The HM Digital TDS meters are using 0.58 when I compare the readouts.

This means that a Hannah meter and an HM Digital meter will give slightly different readings for the same water! Oh well, its really only important to have relative results anyway.