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Old 11-03-2005, 09:37 PM
steve
 
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Richard Sexton wrote:
In article ,
Margolis wrote:
hagen or tetra. Hagen is probably a little better, but it takes a

bit more
practice to get it right.


Hahahaha, good one. These things aren't even remotely
accurate. They're thrown off by nitrite (the instrucstions
say so but don't say high or lo) and the color charts
are a function of water hardness, I have to use the something
in between the salt and fresh chart for my water and I've seen
them read zero with a calibrated kn03 stock solution and I've
seen them read zero when a LaMotte kit reads 220ppm.



Well I've seen a three legged dog too...

For my requirements, the AP nitrate test kit and the Nutrafin pH kit
are very accurate. When used properly, they reflect the conditions I'd
expect to see with the variables present. For example:

My tap water test for nitrates is 0
The city water report for nitrates is less than 1

When I was cycling a new tank, the first test to show results was for
ammonia.
Within a week or so, the nitrite test showed evidence there.
A short time later, the nitrite test was back to zero and the nitrate
test was positive for 5ppm.

My 55g tank has supplemental CO2

Tap water pH test is 7.4
My initial KH tests were 35ppm
Is it a mear coincedence that the C02 chart calculated amount is
2.4ppm?
As I began to add CO2, the pH steadily dropped to 6.8. I added some
crushed coral to add buffer, and the KH is now at 55ppm. I've since
tripled the CO2 bubble rate and it is now calculated at 26ppm with a
measured pH of 6.6.

When I had a large fish load, the nitrate tests got up to about 20ppm
on a weekly basis. Now that there are less fish, the test does not
show as much. When I added many plants, the nitrate test came up zero
again so I've begun to add KNO3. It seems to be workin' for my hobby
needs, and the plants and fish sure are healty.

steve