Re: [APD] Total Dissolved Solids vs General Hardness

["S. Hieber" <shieber at yahoo_com>]

TDS (and GH Hardeness and conductivity) meters measure
connductivity  of the water and use a conversion formula to
display the value in ppm for TDS, degrees or ppm for GH and
microsiemens for conductivity. The relationship between
hardness (degrees or ppm) and conductivity (microsiemens)
varies with the particular salts or mineral ions in the
water. 

So you will want to find out what conversion the
manufacturer used -- it might be in the paperwork that
comes with the meter or you might need to contact the
manufacturer. Some meters use the formula:

EC (in mS/cm) = TDS (in ppm) x 0.64

That's just an approximation that's intended to generally
apply reasonably well. 

You could just get a microsiemens-conductivity reading from
the water where you get the discus and then use for your
aquarium a conductivity meter that displays microsiemens.
Forget all the conversions and stick to the the raw day ;-)

Scott H.


--- David Grim <grim1214 at bellsouth_net> wrote:

> Hi Everyone,
> I am receiving an order of Discus in a couple days. I
> have kept and even
> bred these fish in the past, but it has been a few years,
> and the business I
> am getting these from uses a Total Dissolved Solids (TDS)
> parameter they
> like to keep their water within. I'm getting a TDS meter
> for the fish, but
> was wondering if TDS and GH are the same thing or
> different?
> 
> Any help is appreciated.
> 
> Regards,
> David Grim
> 
> 
> _______________________________________________
> Aquatic-Plants mailing list
> Aquatic-Plants at actwin_com
> http://www.actwin.com/mailman/listinfo/aquatic-plants
> 


=====
Christel Kasselmann, 
author of the best current authoritative text on aquatic plants 
will be a featured speaker at 
The Northeast Council of Aquarium Societies 30th Annual Convention.
March 18-20, 2005 at the Marriott Hotel, Farmington, CT
_______________________________________________
Aquatic-Plants mailing list
Aquatic-Plants at actwin_com
http://www.actwin.com/mailman/listinfo/aquatic-plants