n Sun, 15 Feb 2004 01:39:28 GMT, The Kenosha Kid
wrote:

I switched to a Hagen Nutrafin test kit with several different tests
in the same kit. It has a test for NO3 which I used to cover using a
Tetra test kit.

I ran tests for NO3 using both kits on samples from the same body of
water. The new (Nutrafin) kit gave me a reading at or below 5 mg/l
while the Tetra kit gave me a reading at or excess of 50 mg/l.

I repeated the tests twice and got the same results.

Apart from the Tetra kit being a year old are there any other reasons
for these results to be so far apart?


One of my reasons for not doing any regular testing is the variance in
reading between products. Who to believe? I guess the best thing is
stick with one and assume that any movement is real even if the
absolute value is wrong. It would be nice to have a "standard".

My attitude, if the tank looks healthy, take a reading and set that as
the standard for that kit. Then if the tank goes crazy test and
compare to your "standard" to detect if anything has changed.