"Dave S" wrote in message
...

"The Evil Hand" wrote in message
...
Thanks for replying Dave, Its a 180ltr tank. On in the instructions for
the plant food it say's
that half of it is made up of nitrogen derived from nitrate, so I should
be
able to test for nitrate and then double the PPM to find out how much
nitrogen is in my aquarium. Its also a little worrying for that reason.
Does
anyone know if test kits can pass a use by date, as the one I'm using is
three years old?

"Dave S" wrote in message
...

"The Evil Hand" wrote in message
...
Hi, I recently started using flourish nitrogen plant food as the plants
in my aquarium stopped growing due to the nitrate level dropping to
0ppm. On the label it says that it contains two sources of nitrogen,
one being from nitrate and that you can use a nitrate test kit to tell
how much nitrogen is in the tank by doubling the reading. But I am
still unable to get a reading using my Hagen test kit, even when I add
the plant food directly into the test tube?

Does anyone know why that is?

cheers
Evil Hand
What's the capacity of your aquarium?


I think your under-dosing. according to my calculations (and according to
the instructions for a beginner), you should be dosing 1.1mL - 2.3mL x
twice weekly. Therefore if your dosing at 0.5mL there's a discrepancy. I
have the same problem as you: Little or no NO3 reading and I'm using
Seachem Nitrogen and testing with Hagen.

Instead of dosing twice/week (as recommended), last week and this week I'm
dosing EVERY DAY at treble dose, and although I've noticed a significant
improvement in my plants, NO3 remains at 5ppm. I don't have too much
confidence in my Hagen test kit even though it's in date.

I'm not sure if this helps you, but just to let you know that others have
the same problem.

Regards - Dave


FWIW - The NO3 test kit I am using is date expired 30 June 2007 - remember
my readings were 5ppm. I've just been out and purchased a new test kit
(date expired 31 July 2008 and my reading now is 20-50ppm - way to high. I
think I'll do a water change and reduce my Nitrogen!

Regards - Dave