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Re: Lamotte CO2 kit



Roxanne wrote:
"The Lamotte CO2 kit,
which I own and have used to test natural waters for research, may be
inexpensive, but requires titration and most people will be put off by
that.  It's not that hard, but it is definitely more trouble than it's
worth for home use."

Titration is difficult or troublesome??? The LaMotte CO2 kit is relatively
easy to use, and the endpoint of the titration is quite visible in good
light and against a pure white backgound (the endpoint has been reached when
the pale pink color of the test liquid disappears and the liquid becomes
colorless). The biggest "got-ya's" with the kit are to ensure that the
reagents are fresh (I've gotten bad results with old reagents), you are
careful about taking the water sample (you don't want to lose the CO2 until
you've had a chance to measure it) and you have good light and the proper
background (white) to determine the endpoint of the titration. Oh yes, you
have to be able to count too.....the CO2 concentration is proportional to
the numbers of ml. of titrant used.

When "guesstimating" the CO2 values from the chart, it assumes that both the
KH and pH values are precisely known with a high degree of accuracy
(especially the pH) - small mistakes can lead to large variances in the
estimate of CO2 present in the water. If someone is sloppy, there are 2
places here to make a mistake (KH test and pH test), which would only add to
their worries.

Luckily, there isn't a "specific" amount of CO2 which needs to be present in
water to be useful - the range over which CO2 is both helpful to the plants
and safe for the fish is quite wide.

If being careful enough to be able to use the LaMotte CO2 kit is beyond
someone's ability, they might be better off with plastic plants (and fish to
boot).

Just a thought.....

James Purchase
Toronto