PlanetCatfish.com

Hi I came across this profile for Panaqolus Maccus - the clown pleco

https://www.planetcatfish.com/common/sp ... ies_id=734

And the hardness figure is stated as 3000mu during the dry season - I don't know what this measurement reflects and can't find anything online? Does anyone know what it means and how it would translate to Gh or ppm etc?

Wills

I don't know, but I only know three folks that have been to the Rio Tinaco and one of them was me and I didn't measure it.

@Shane, was this from you by any chance?

My guess would be this should be 300µS.

Jools

Ah wow that is interesting! Just to dumb it down a bit further what would 300µS mean - I mean I definitely know what it means but just incase we have some less well read people reading this... ok I'll be honest I don't even know what that u symbol is...

I'm still guessing it means this, but µ means micro and S is for Seimens. So a conductivity of 300 microSeimens. I don't know why it was written as 3,000 mu.

See:
https://www.planetcatfish.com/general/g ... nductivity for a bit more on conductivity.

HTH,

Jools

Definitely thank you. Just to try and wrap my head around it what sort of scale do microSiemens measure in? Eg would 300 microSiemens indicate a high TDS?

Wills

@Wills, TDS stands for "total dissolved solids" and is expressed in parts per million (ppm). The other number is "conductivity" which is expressed in units of Siemens per meter (or in this case microSiemens per centimeter). The two numbers are related but not always the same.

TDS refers to all molecules dissolved in the water. Some molecules may be electrically charged and thus contribute to the ability of the water to conduct electricity (thus conductivity); other molecules in the water may not be electrically charged, so they have no impact on conductivity values but they still contribute to TDS.

Theoretically, if all the molecules in the water are electrically conductive, the ppm reading and the uS/cm reading would be directly proportional. But since some molecules are not conductive, that changes the proportionality between the numbers. For example, I have a Hanna brand electronic meter for measuring TDS and conductivity. The device allows me to set two different calibrations, one which assumes TDS = 0.45 x Conductivity (so a water with TDS = 90ppm would have a conductivity of 200 uS/cm) and the other calibration which assumes TDS = 1 x Conductivity (so a water with TDS = 90ppm would have a conductivity of 90 uS/cm). My instrument comes from the factory set to the 0.45 conversion factor, so I leave it there.

Since most people don't know what's in their actual water in terms of soluble contaminants, it's pretty safe to leave the TDS/conductivity conversion at its the factory setting.

I hope that's helpful.

Wills wrote: 29 Aug 2023, 22:19Just to try and wrap my head around it what sort of scale do microSiemens measure in? Eg would 300 microSiemens indicate a high TDS?

Wills

Also, I have a spawning report for , HERE. My report lists the water conductivity at 600-700 uS/cm during spawning. Although it was a while ago when I took those readings, I recall my tank would routinely exceed 1000uS/cm... not intentional dry season simulations, but rather just pretty hard water at home plus missed water changes. Fortunately, clown plecos are pretty tough fish, forgiving in situations like that.

Cheers, Eric

So I am the source.

"The Tinaco was very low the day we collected. Norbert said that this was the lowest he had ever seen the river. In places, it was actually possible to jump across the river. The river had a substrate of sand and gravel with several large driftwood snags. The temperature was about 80F, pH 7.5, and the water surprisingly hard at close to 3,000 mu. The reason for the higher pH and hardness is that the Tinaco origintaes in the mountains while the Santo Domingo just takes drainage from the surrounding plains. "

Keep in mind that the reading was taken at the height of an abnormal dry season after the water had spent months evaporating in the tropical sun thus greatly increasing the TDS present. It should not be used for routine aquaium care but rather as an example of how extreme water conditions can become in the llanos during dry season. No idea why it shows as "mu."
-Shane

Hi all,

Shane wrote: 30 Aug 2023, 11:59 ....... the water surprisingly hard at close to 3,000 mu. The reason for the higher pH and hardness is that the Tinaco origintaes in the mountains while the Santo Domingo just takes drainage from the surrounding plains. "

...... No idea why it shows as "mu."
-Shane

I'm guessing that the "mu" is from the greek letter "mu" μ that we use as the symbol for <"micro">, so that would be 3000 microS (3 milliS), which is pretty salty.

The other option is "mho", before the SI unit for conductivity was "siemen" it was "mho", which is "ohm" backwards, because electrical conductivity is the inverse of electrical resistance.

cheers Darrel

Shane wrote that in most cases the dissolved matter has an electrically charge.

That is right - but the most important exception is peat. In blackwater, the conductivitiy is low. 1 or 2 microsiemens per cm. But a lot of meat is dissolved, which does not reflect on the conductivity.

As a TDS machine measures conductivity, and than expresses the results as TDS, I would suggest doing a little experiment - measure the TDS of a cup of water, and then add some sugar to it. Sugar is also an unchaged molecule. I would expect the machine will not detect any difference.

Therefore it is better to say conductivity, as the not charged solids are not seen.