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Cautionary note on using online nutrient calculators

Discussion in 'Aquatic Plant Fertilization' started by Solcielo lawrencia, Sep 3, 2013.

  1. Solcielo lawrencia

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    Don't ever assume they are accurate. I just found out I was actually adding twice the amount of iron into my tank so 1.5ppm of iron was actually 3ppm. Yet Another Nutrient Calculator used the information about Easy Life Ferro from the manufacturer's website which turned out to be inaccurate.

    I emailed Easy Life about the discrepancy between what was labeled on the bottle and on the website and here's their reply:
    "Thank you for your interest in our Easy Life products.
    The label on the bottle correct, we have to change the info on our web site."


    Easy Life Ferro is the same concentration as Seachem Flourish Iron so using Seachem in the calculator yielded the correct dosage amount.

    HOWEVER! if you select Flourish Iron and calculate for EI, you'll get how much you should dose in mL. But if you use that amount to calculate the result of your dose, you'll get an entirely different concentration. E.g. for 10 gallons, dosing EI indicates adding 1 mL to reach .50 ppm of iron. Input this amount in "the result of my dose", you'll get .26ppm, which is half the amount! Which is correct? You'll have to do math to figure it out.
     
  2. Tom Barr

    Tom Barr Founder
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    Which dosing calculator? Wet's?

    Let's fix it and let him know if so.

    Seachem and Easy life can fix their own stuff, they have chemist:)
     
  3. Tom Barr

    Tom Barr Founder
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    Which dosing calculator? Wet's?

    Let's fix it and let him know if so.

    Seachem and Easy life can fix their own stuff, they have chemist:)
     
  4. Solcielo lawrencia

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    It was Yet Another Nutrient Calculator, rota.la/
    I sent in the correction the other day but I haven't received a response. And Easy Life's website still hasn't been updated.:confused:
     
  5. Tom Barr

    Tom Barr Founder
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    Seachem is good about this stuff, EL may not be.
    Wet will get back and update I'm sure.
     
  6. Tom Barr

    Tom Barr Founder
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    Seachem is good about this stuff, EL may not be.
    Wet will get back and update I'm sure.
     
  7. Tug

    Tug Lifetime Charter Member
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    Measure twice, cut once.
     
    #7 Tug, Feb 24, 2014
    Last edited by a moderator: Jul 3, 2014
  8. tefsom85

    tefsom85 Lifetime Members
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    Speaking of cautionary..

    Every time I try to visit Wet's calculator, McAfee flags it as a risky site. So, I don't use this. Anyone else have this issue?
     
  9. ShadowMac

    ShadowMac Lifetime Members
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    I get the same notice sometimes. I ignore it. Most likely because it is an unknown website. There are no downloads or weird links. Been safe for me.
     
  10. Tug

    Tug Lifetime Charter Member
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    I've nothing I can point to that would keep me from using it.
     
    #10 Tug, Feb 24, 2014
    Last edited by a moderator: Feb 25, 2014
  11. Solcielo lawrencia

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    I just used Wet's calculator and it's getting vastly different results than before. Certain fertz are reading double the PPM than it used to such as KNO3 and KH2PO4.
    E.g.
    1/8 tsp KNO3 for 10 gallons = 21.36ppm of NO3

    What's going on here?
     
    #11 Solcielo lawrencia, Apr 25, 2014
    Last edited by a moderator: May 11, 2014
  12. Tom Barr

    Tom Barr Founder
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    +1 one, unknown personal site, that's why.
     
  13. Solcielo lawrencia

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    The calculator is reading normally again:
    1/8 tsp KNO3 for 10 gallons = 10.53ppm of NO3

    However, The AquaTools' calculator is double this. Which calc should I believe?
    After measuring my NO3, I believe that the double reading is correct.


    Edit:
    NVM, converting from tsp to grams was the issue.
     
    #13 Solcielo lawrencia, May 11, 2014
    Last edited by a moderator: May 11, 2014
  14. Petex

    Petex Member

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    Wets calculator has bugs:
    [​IMG]
    http://img5.fotos-hochladen.net/uploads/nutritioncalcuq8spuln9jm.jpg

    Example Tropica fertilizer,
    if you pick "Ei daily" it says 3ml Tropica add 0,01ppm Zn and 0,01ppm Mo.
    if you pick "Estimate index" it says 7ml Tropica add 0,01ppm zn and 0,01ppm mo.
    The Zinc + Molybdenum ppm rates still dont change or update on Wets calculator (for TPN).
    (btw. the copper results are also wrong)

    Same with other fertilisers:
    For example Vimi All-in-One: Po4, iron and Boron results on Wets calculator are wrong.
    1ml Vimi on a 50L tank adds 0,08ppm Po4 and not 0,6ppm. I would be carefully with this calculator depending on the fertiliser or dry stuff you use.
    It may give you still wrong results.
     
    #14 Petex, Jun 5, 2014
    Last edited by a moderator: Jun 6, 2014
  15. PhilipS

    PhilipS Lifetime Members
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    Is rota targeting a higher Fe across the board or just one product?

    I rely on that calculator to mix dry ferts.
     
  16. Tom Barr

    Tom Barr Founder
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    I still measure the weights of the teaspoons I use if I want to be sure. Then do the rest by hand.
    The weight differences with teaspoons and powders can vary.

    But such variation should never cause an issue for plants or algae............
     
  17. Wet

    Wet Lifetime Members
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    Sorry I haven't been around, just away from the hobby. I'm also sorry I've not kept up with these bugs.

    zorfox sent some awesome pull requests/bug fix to fix values. The double teaspoon weight mentioned here was because I accepted a pull request that was calculated incorrectly. The nature of the project is that it's based on contributions made, and if you ever want to add anything you can do it easily here: https://github.com/flores/yet-another-nutrient-calculator/blob/master/constants/commercial_products.yml

    Petex, the 0.01ppm for Zn there is indeed my non-rounding error. Actually anything between 0.00 and 0.01 becomes 0.01 in the results because it's my lower bound after rounding all values above that for the interface. I'll fix that and make it say "
     
    #17 Wet, Jun 9, 2014
    Last edited by a moderator: Jun 9, 2014
  18. Petex

    Petex Member

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    Not all are non-rounding errors, because if you compare TNP and TPN+ you will get different Cu/zn results.
    Since both products contain the same % Cu/Zn ratio, it just means yours calculator, calculates one Tropica product at last wrong.
    Vimi All-in-one declaration: 1000 ppm P
    --> 0,001l x 1.000ppm / 50l = 0,02mg/l P x 3.06 = 0,08mg/L Po4
    1ml adds 0,08ppm Po4 to a 50liter tank and not 0,6ppm

     
    #18 Petex, Jun 11, 2014
    Last edited by a moderator: Jun 11, 2014
  19. Wet

    Wet Lifetime Members
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    Petex,

    1) Your math in the example should be 0.0612 and not 0.08ppm. And you're right: the concentration for P specifically was off by a factor of 10. This is fixed here and live: https://github.com/flores/yet-another-nutrient-calculator/commit/b87893bcdce8dd7d8e2e6bfd98658600c8cce079

    2) I'm not sure what you would prefer then for the output, but check out rota.la now. Does this fit your requirements?

    [​IMG]

    What do you think? Does that work for you?

    Re: precision: you have to understand that there is a wide variety of people using these calculators, and plenty of people have complained about too much or too little precision. The change above extends the number of significant digits for rounding to 4 past the decimal if the value is under 0.01. If you have a constructive idea it is appreciated. Likewise, if you see incorrect values you should feel free to fork on GitHub and add the code. Frankly doing this in the code base is much easier for me than tracking forums around the Internet at this time and it's too difficult to expect one person to know when any manufacturer changes something.

    More bugs, reports, and fixes are appreciated.
     

    Attached Files:

  20. Petex

    Petex Member

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    Great that you fixed it.
    And yes, it was certainly 0.0612ppm - imo also B, Fe from the Vimi should be checked
    Tropica: The marked nutritions are also wrong in yours calcluator.
    [​IMG]
     
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