Water Chemistry: Osmoregulation, Ionic Imbalance & pH

[dw1305]

Hi all,
I've found a useful article on water chemistry, it is well worth a read:

"Water Chemistry: Osmoregulation, Ionic Imbalance & pH" in "The New England Cichlid" A NEW ENGLAND CICHLID ASSOCIATION PUBLICATION April 1, 2011.
<http://www.tbas1.com/Exchange/The%20New%20England%2011.pdf>.

The link was originally posted on the UKAPS forum <http://www.ukaps.org/>, and the article was written by Joe Gargas.

cheers Darrel

 

[Scree]

Good read, cheers for sharing dw

 

[raymond82]

Very nice article, it leaves me with a question though: my (cheap ebay) TDS and conductivity meters read 107 TDS and a conductivity of 210 in one of my aquariums. This makes the conversion factor ~0.51. Since both of them probably measure conductivity and the TDS meter uses a fixed (factory preset) conversion factor, would it better to rely on the conductivity meter?

 

[dw1305]

Hi all,

This makes the conversion factor ~0.51. Since both of them probably measure conductivity and the TDS meter uses a fixed (factory preset) conversion factor, would it better to rely on the conductivity meter?

I always use conductivity. You are right about the conversion factor, it depends upon the salts. I think that 0.51 is the value for NaCl.

Have a look here: <http://www.appslabs.com.au/salinity.htm>, towards the bottom of the page.

cheers Darrel

 

[raymond82]

Thanks a lot Darrel, that's very interesting. I used the measurement of bottled water (33 mg/l) as a reference for my ppm TDS meter (which read ~31 ppm TDS), I just checked and it has 3 mg/l Na and 5 mg/l Cl. So I guess the conversion factor of my TDS meter is set to the one for NaCl. I just saw that with the Hanna Combo meter you can pick your own conversion factor, I guess I should start saving up for something like this.

I'll use the conductivity meter from now on. When I see people mentioning their water values in ppm on a website or forum, would it be save to assume that the value in conductivity would be this divided by 0.67?

 

[jmtrops]

Yes the TDS meters are really just conductivity meters. If you are using a TDS meter the manufacture should tell you what there convertion factor is and they can range from .50 to .65. Your local water company will publish there convertion factor based on the proper way of measuring TDS for your water suply. the problem with these meters is they are measuring all of the organics in your water and you still need to be aware of your KH. My tap water is 100 us but it has all most no KH.