nitrate test kits

valerie

AC Members
Apr 18, 2001
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Edmonton, AB
I think i'm having soem problems with nitrate test kits. I have an aquarium phamiceuticals test kit and a Hagen est kit and they both give different readings.

the AP nitrate kit reads <5ppm and the hagen test kit gets so dark it doesn't match and of the colors,not even the darkest which is>110ppm. What is going on? I jsut bought the hagen one 2 days ago so it can't be expired.

What kind of test kits do other people use? What might be happening with mine?
 
Are you trying to match the colours in natural sunlight? The colours on my Hagen tests look very different under incandescent lighting.
 
I have purchased both an ap and a seachem test kit that gave false low or zero readings. My first ap nitrate test seemed to work really well but the next one didn't.
even the ap test when fresh? can be a little tricky to follow the exact procedure, read the instructions very carefully.
good luck
:)
 
Valerie, I'm hoping that your post isn't a harbinger of things to come.....I recently started using an AP nitrates kit and it works really well...helps me get a handle on how much nitrates my plants are using. The instructions seem fairly simple. Ten drops of each in the test tube, shake em up and wait a few minutes. It works well for me. One thing that I wanted to mention....make sure you shake bottle number 2 really well before adding that re-agent. They make a point of how important that is. I'm just hoping that the next AP kit I buy is consistently accurate as this one.
Len
 
Originally posted by djlen
...The instructions seem fairly simple. Ten drops of each in the test tube, shake em up and wait a few minutes. It works well for me. One thing that I wanted to mention....make sure you shake bottle number 2 really well before adding that re-agent. They make a point of how important that is. Len

You definately have to shake bottle #2 for at least 30 seconds or you get false readings. Plus, the reagent in bottle #2 seems to go stale after a period of time.

good luck
:)
 
I use Tetratec test kits. I have the Master test kit(pH, Ammonia, Nitrate, GH/KH). It works fine for me and the instructions are very easy to follow. The vials that come with it are rectagular so they lay flat against the color cards, something I did not like with the AP tubes. I have not tried the Hagen test kits yet.
 
I normaly really like Salifert Test kits, but I got the Nitrate kit and it is way too hard to distinguish colors. I also don't seem to get as high a reading as with my other kit that's almost empty (Red Sea). I am very disappointed with this particular kit but have been happy with the pH and KH/Alkalinity test kits.
 
Give AP a call and ask them how long the regent in the test kit lasts. You may have bought a kit that is expired. I have called AP and asked them about expiry dates and they told me that it is different with different test kits. They told that the last four digits of the lot number is the month and year of manufacture. For example I was told that the fresh water pH test kit is good for 5 years after date of manufacture, High range pH test kit for 3, and nitrite test kit for 3. Hagen test kits usually have an expiry date on the bottom of the box.
 
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