Re: [Killietalk] K. marmoratus - Collection and Water Testing

[Brian Watters <bwatters at shaw_ca>]

Pablo Robles wrote:

>
> The collection site is a couple hours from home but very easy to get to.
> I may go there and measure the water again in January right there in the
> spot. What handheld instruments do you use? Brand? Model?
>

Over the years, we have used a variety of instruments but mostly we use
those with the "Oakton" brand name. I have also used various meters by Hanna
Instruments. There are a variety of models of all these handheld meters
depending on what features you need (waterproof or not, temperature
compensation or not, etc.) and how much you are prepared to spend. I would
suggest that you go to the websites of scientific supply companies and look
at their online catalogs. I have always purchased mine through Canadian
laboratory supply companies but that may not be the most convenient for you.
Do a "Google" search for such companies and see what comes up.

I have separate instruments for pH, Temperature, TDS and uS. The latter two
properties, as measured by these handheld meters, are both based on
conductivity and there is a built in mathematical relationship between the
two which, in reality, may not be true in all cases.

One instrument that I have also used is a combination meter by Hanna
Instruments that combines the functions of pH TDS, uS and Temperature in one
small handheld, waterproof meter (Go to http://www.hannainst.com). This
works well. My only complaint is that it will not accept an extended
temperature probe, which makes it difficult to determine the temperature at
various levels in the habitat. And that can vary enormously.

>
> Already measured conductivity to be 3400 uS and 7.46 pH. Checking in
> wikipedia seawater is 50,000uS/cm and drinking water is up  to 500uS/cm.
> The place was flooded due to recent rains. I guess that's why water was
> more to the fresh than to the salt side. Just to get a feeling about how
> different is this water. What would be a typical, notho habitat
> conductivity?
>

I have water quality data for a few hundred Notho habitats in about 10
different countries and the averages, based on those data, are:

pH = 7.4
TDS = 94 ppm (excluding a few extremely high values that would skew the
data)
uS = 190
Temp. = 26 C (~ 79 F)

Obviously, there is a fair range in values for all of these, but I am not
going to get into the statistics of the data here.
___________________________
Brian Watters
6141 Parkwood Drive
Nanaimo, BC, V9T 6A2
Canada
Ph: (250) 760-0564
E-mail: bwatters at shaw_ca

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