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Re: Lamotte vs AP

Anyway, before I was so rudely interrupted...

Cavan made some legitimate comments that I'll comment upon as gently as

"I thought I would save the money and
get the AP kit.  I couldn't tell between 5 and 15.
There's a big difference between those two numbers."

No, there's really not much difference between those numbers. See the info
presented by The Good Tom (Barr) at


The range is very flexible, up to 20 ppm at least.

"The lamotte kit is more reliable too.  I was getting a
reading of what I thought was 5 from the AP and
Seachem kits.  Why did I have so much green dust then?
 Testing on a friend's Lamotte showed it was actually

I'm curious as to how you could get a reading of 17. My LaMotte has
increments of .25, .5, 1, 2, 4, 6, 8 and 10. These have to be multiplied by
4.4 to get a NO3 reading. If the color doesn't match 2 or 4 but falls in
between, then what is the right factor? 2.1? 3.9? That gives a range of
about 9 to 17. Suddenly that precision measurement isn't so precise any
more. Although it may be accurate, which is something else. Similarly, the
AP color chart can be construed such that a reading of 10 could be read as
"around 10". I agree that the colors of 20 and above are impossible to read,
but it doesn't matter. All those readings are simply "too much" anyway and
the actual numerical reading doesn't matter. As long as NO3 is in the 0-20
range, the AP kit will tell you what you need to know, which is that NO3 is
in the 0-20 range. I'd look elsewhere for the green dust problem.

So I still say that the LaMotte is overkill and overpriced. And it's not all
that precise anyway. My opinion, take it or leave it.

Evil Tom