Nitrate but no nitrite? (fishless cycling)

"Bill" wrote in message
news:gAiYd.70979$Tt.49598@fed1read05...
Hi all,

I'm doing a fishless cycle on my 20H tank. I've been testing ammonia
and nitrite daily, but haven't been testing nitrate very much. I
figured there wasn't any point to it until I saw nitrite, and the
nitrate test is a royal pain to do -- it's the Aquarium Pharmaceuticals
test, where you have to add 10 drops of one solution, shake the 2nd
solution for 30 seconds, add 10 drops of it, and shake the test tube
for
another minute.

The last time I tested nitrate was March 4th, when I first added the
ammonia, and the result was 0 ppm. Since then, I've done daily ammonia
and nitrite tests and gotten 4 and 0 ppm, respectively. On March 6th,
I
dropped some food in the water to add a little phosphate to the system,
based on http://tinyurl.com/53dvn, http://tinyurl.com/4z65a, and
http://www.algone.com/fishless_cycling.htm; I also adjusted the
temperature from 80F (set there from 78F the day before) to 82 (to
promote the bacterial growth), and it's been fluctuating 81/82 (by
whole
degree) since then. However, it's actually been less than about half a
degree on the analog thermometer I have on the tank.

Keeping in mind that my tap water tests negative for nitrate, I tested
the big three last night. I read 4 ppm ammonia, which I expected, 0
ppm, which I also expected, and about 2.5 ppm (maybe 1-2.5) nitrate,
which I most certainly did *not* expect. On the card, it matched
neither the bright yellow of the 0 reading nor the light orange of the
5
reading. It was slightly orange and certainly darker than the bright
yellow. Keeping in mind what NetMax said about the differences in
color
perception between males and females, I saved the samples to show to my
wife, who was out at the time. She agreed with me.

I shook the second bottle of nitrate test solution vigorously for 30
seconds and the test tube for one minute, as directed. (I timed it.)
I'm also positive of the nitrite test results, and it's only been just
under a week since I first added the ammonia. I can think of three
possibilities, the first and simplest of which is operator error.
Second, it could have been the decaying food producing nitrate directly
-- the water smelled less strongly last night than it had for the first
few days after adding the small amount of food (what would be probably
three or four feedings' worth in a fully-stocked 20 gallon tank).
Third, and least likely, IMO, is that the bacteria are responsible for
it, even though I have no measurable quantities of nitrite yet.

Anyone have any ideas?

I agree that the NO3 test is a PITA (FYI: and if you leave the solution
to sit, it gets darker). I wouldn't worry about a few readings which
don't quite fit. Cycling is proven when you have no NH3/4, no NO2 and
lots of NO3. There are many things which can skew the results in
between. Aerobic nitrifying bacteria is in the air (and in higher
percentages if you already have fish, like your Bettas), and if you have
more of the nitrospiras for some reason (like when you added Stress-Zyme
which I think is a wide spectrum bacterial mix), then they could be
moving the NO2 to NO3 faster than expected.

When you think it's cycled, you can add some ammonia (about 2ppm) and
check to see if it has been converted to NO3 after 24 hours.
--
www.NetMax.tk