Ideal values for NPK

Discussion in 'Aquarium Fert Dosing' started by Jack middleton, 1 Nov 2009.

  1. Jack middleton

    Jack middleton Member

    Messages:
    172
    Hi, I'm just wondering what are the ideal values for N, P and K in a high Tech, densely planted aquarium?

    I'm just asking as I'm working out how many grams of each substance i should put in my own PMDD+PO4 solution to achieve appropriate levels

    I have so far gathered that 1ppm is appropriate for PO4 but I see people with tanks that have levels of around 3ppm

    I don't have the means to test phosphate so I'm purely having to estimate it.

    I know my tap nitrate is 10ppm so I don't know how that would affect things.

    Cheers, Jack
     
  2. aaronnorth

    aaronnorth Member

    Messages:
    3,955
    Location:
    worksop, nottinghamshire
    PO4 - 2ppm
    NO3 - 20ppm
    K - 20-30ppm

    those are avergaes, maximum uptake values per day are

    PO4 0.5ppm
    NO3 5ppm
    K not sure!

    they are calculated on a 4wpg tank with non limiting CO2 levels so your plants wont/ shouldnt ever need more than that per day.
    As long as you dose enough KNO3 and KH2PO4 then i would worry about hitting levels for potassium, there is usally enough in tap water.
    nutrient levels already in tap water isnt generally taken into account, but if you feel there is enough NO3 in the water then you dot have to dose any but use KH2SO4 instead for a source of potassium
     
  3. Jack middleton

    Jack middleton Member

    Messages:
    172
    Cheers, Aaron
     
  4. Jack middleton

    Jack middleton Member

    Messages:
    172
    This is FSO's KNO3 breakdown

    Potassium Nitrate (KNO3) contains 13.9% nitrogen (N) and 38.7% potassium (K)

    What makes up the remaining 47.4%?
     
  5. JamesC

    JamesC Member

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    1,276
    Location:
    Bexley, Kent
    O
     
  6. Jack middleton

    Jack middleton Member

    Messages:
    172
    thats confusing me now :?

    Why have they not just made the values up so they equal 100%?
     
  7. Jack middleton

    Jack middleton Member

    Messages:
    172
    I've just made myself feel stupid!

    O is the oxygen :oops:
     
  8. Dolly Sprint 16v

    Dolly Sprint 16v Member

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    Location:
    Cheshire

    So if you tap P04 levels are greater than the above reading of 2.0 ppm what do you do.

    Regards
    paul.
     
  9. aaronnorth

    aaronnorth Member

    Messages:
    3,955
    Location:
    worksop, nottinghamshire
    nothing, it is just an average for non-limiting levels.
    Higher levels may not be necassary because the plants can obtain all the Phosphorous they need, thats not to say in every case it will satisfy you as some people run lots of lighting and plant species can affect it - ie, a tank full of fast growing stems

    thanks, Aaron
     
  10. Jack middleton

    Jack middleton Member

    Messages:
    172
    I have another question (sorry)

    I have used Clives recipe for the 20ppm No3, 2ppm Po4, 30ppm of K and, Appropriate levels of CSM+B in fractions of teaspoons, but how do i convert each of these values into mass?

    Thanks for the help
     
  11. Dolly Sprint 16v

    Dolly Sprint 16v Member

    Messages:
    1,611
    Location:
    Cheshire
    Thx Arron

    so a good conclusion to this thread would be to:

    Tailor your fertz / co2 / lighting to suit the plant requirement or buy plants to suit your water parameters (which inc. partial fertz) co2 /lighting :thumbup:

    Regards
    Paul.
     
  12. aaronnorth

    aaronnorth Member

    Messages:
    3,955
    Location:
    worksop, nottinghamshire
    taken from James' website:

    Teaspoon quantities
    I have calculated the amount of each chemical by weighing the amount using a standard teaspoon (5ml) which is available from most kitchen stores. Depending on where you obtain your chemicals from you may get slightly different weights. I get all mine from Aqua Essentials. Here are the weights I have used for each chemical using one teaspoon:

    Potassium Nitrate 6.0g
    Potassium Phosphate 6.6g

    yes, although i am not quite sure i agree with the second half, because usually we tailor our water parameters for the plants.
     
  13. ceg4048

    ceg4048 Expert/Global Moderator Staff Member

    Messages:
    8,953
    Location:
    Chicago, USA
    Jack,
    First of all, there are no "ideal values". You really need to purge this concept from your programming because it will ultimately lead you astray. You cannot talk about ideal values outside of the context of the other environmental conditions against which each plant is facing. Additionally, you need to be aware that each species and each specimen in the tank have different uptake efficiencies and different requirements. The EI dosing scheme has nothing to do with ideal. The dosing values developed after the experiments were complete demonstrate a worst case scenario. The scenario is one in which the environmental stresses are extreme, and in which the demand for growth rate are at it's ultimate expression. This is not the same as, nor should it be interpreted as "ideal".

    As stated in the EI tutorial, we need to think about nutrients in exactly the same way as we think about food, because that's what they are. So now, change the wording of your question to: "What is the ideal level of food?" Can you see how incongruous this question now becomes? The ideal level of food required by a marathon runner will differ from that of a couch potato. Ideal will depend on what goals you have for growth rate and maintenance. So if I want high growth rates then "ideal" will be a higher value than if my goal is low maintenance. If my tank has low light then ideal will be a lower value than if the tank were highly lit.

    The EI dosing values therefore are a worst case baseline set of values that ensure no deficiencies and from which we are encouraged to deviate in order to balance growth rates and waste production with our maintenance requirements within the context of flow rates, lighting, and CO2 availability.

    Plants have a wide range of nutritional requirements and many dosing values can be used. As long as you don't go below the minimum requirements for that particular environment condition then any value you dose can be considered ideal.

    Generally speaking a teaspoon of the powders weigh approximately 6 grams. So use this as a conversion factor for changing teaspoon values to grams.

    Cheers,
     
  14. CeeJay

    CeeJay Member

    Messages:
    945
    Location:
    Surrey UK
    Hi Jack

    Or you could just use a teaspoon :lol:

    On a serious note, Clive gave me loads of advice when I was starting down the EI route about 6 months ago, when I was stressing about 0.2 grams of this and 0.4 grams of that etc.
    After the penny finally dropped :oops: , I went over to teaspoons or parts thereof, and now I just go to the nearest 1/4 or 1/8th of a teaspoon, and have to say I have had great results.
    As Clive says, non limiting is the key for our own particular set ups.
    I used to weigh my powders, but I can count teaspoons a damn sight quicker :D .

    Chris
    Keeping it simple :D .
     
  15. Jack middleton

    Jack middleton Member

    Messages:
    172
    Thanks clive, excellent reply!

    It all seems a lot clearer now!

    I have been rounding up values to he nearest 1/4 of a teaspoon, I just need to buy some DI water and some dosing spoons now,

    Cheers, Jack :thumbup:
     
  16. ceg4048

    ceg4048 Expert/Global Moderator Staff Member

    Messages:
    8,953
    Location:
    Chicago, USA
    Yep, I concur with the rounding method. This is one of the reasons it's called "Estimative" Index. :D

    Quite frankly I wouldn't even bother with the DI water, especially if you have to buy it. Anoraks like JamesC obsess over knowing the exact values in their test tubes. Barbarians like myself figure it's just another case of being Estimative. Save your pennies to buy an extra bag of crisps to munch on while watching your plants grow. :wave:

    Cheers,
     

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