Advertisements
Aquatic Avenue Banner Tropica Shop Banner Fishy Business Banner
Results 1 to 2 of 2

Thread: Disparity between results from NO3 Test kits

  1. #1
    Join Date
    Apr 2003
    Location
    Singapore
    Posts
    43
    Feedback Score
    0
    Country
    Singapore

    Disparity between results from NO3 Test kits

    Advertisements
    Fresh n Marine aQuarium Banner

    Advertise here

    Advertise here
    Hi,

    I have a Tetra NO3 test kit which I bought about 2 weeks ago, and a Sera NO3 kit that I bought last week. Out of curiosity, I tested my tap water, and the test turned up 12.5mg/l on the Tetra, and 5mg/l on the Sera. I was scouring through the forums, and discovered that the solution had to be shaken (not stirred [:] ) vigorously after the power reactant was added. So I re-did the tests, taking care to shake, and swirl gently as required. The results were the same.

    Which test kit should I trust? I am quite doubtful of the results of the Tetra kit as it detects 12.5mg/l in my tank water even after 9hrs of vigourous photosynthesis.

    So what should I look out for when buying these kits? Which retailers are the ones that tend to have newer stock?

    Are the expiry dates printed on the test kits?

    TIA.

  2. #2
    Join Date
    Feb 2003
    Location
    USA
    Posts
    1,198
    Feedback Score
    0
    Images
    7
    Country
    United_States
    I would not trust either kit.

    They are okay for general levels that might be toxic to fish, say 50ppm+ etc but they are not good for NO3 measurements for planted tank like most pH test kits as well.

    Lamott, which might be rough to find there, and then would run 100$SD perhaps, is a good kit.

    But there's ways around dealing with junky test kits. The tap wate rcompany has measurements for their water. Call and ask them with the N-NO3 levels are.

    From there you know what the tap water has, all you need to do is add KNO3 to get a good range of NO3.

    Say you have a 100 liter tank or so with gravel etc. Adding 1/4 teaspoon of KNO3 will give you about 10-11ppm.

    If the CO2, K, PO4, Traces are good and being added a regular rate, you can figure the maximum amount used of NO3 will be 3-4ppm or so per day.
    So each 1/4 teaspoon will give you about 2-3 days worth at the plants maximum growth rate.

    Now your plants may not be growing at the max rate but this is alright. Your regular 50% weekly water changes prevent any _significant_ build up and the dosing near the max uptake rates prevents any significant deficiencies.

    And you don't need to test which no one really likes to do anyways.

    The accuracy of my method is roughly 1-2ppm of NO3, not bad, actually better than most any test kit out there.
    1-2ppm will not make or break a planted tank unless you've been out and sitting at zero ppm NO3 fro more than a day etc.

    You do a similar thing with dosing PO4, K, Traces etc.
    The key is having good CO2 and a fair close tabs on the NO3. The K, PO4 and Traces levels are more robust and flexible.

    I'd spend my test kit money on a pH monitor.

    Hope this helps.
    Regards,
    Tom Barr

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •