NO3 Salt Petre Question

Discussion in 'Plant Problems' started by Kryo, Nov 4, 2013.

  1. Kryo
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    Kryo Green fingers

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    Hi Guys

    Ok so I'm getting back into the hang of things with dosing the new tank. And have a NO3 question and I need all the scientists out there to help me out here! :embarassed:

    My new tank is 600L. 592L actually, but with a 25L canister and another 12L canister it evens out to about 600L after displacement. Inert substrate!

    I am dosing Tropica Premium as my main fert. Premium doesn't have added NO3 or P. With the Discus I didn't want to eventually have a repeat scenario of my previous tank but want to have more control over NO3 and P, so I'm dosing EI of those two.

    I have a mixed batch of Salt Petre. 100g -> 500ml Distilled. Which according to my test kit gives me between 20ppm-40ppm per 5ml of NO3 so lets say it gives me 30ppm.

    My question is: With the mixture above how many ppm's of NO3 needs to be added daily to get it to a stable 5 - 10ppm???

    Can someone help me out with a formula? I can usually do this stuff but I'm battling with this one for some reason! I know this will need to be adjusted as time goes by but I just need a starting point for now!

    Thanks in advance!

    Cher
     
  2. tyronegenade
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    tyronegenade Specialist

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    Potassium nitrate is 1 part K and 1 part NO3. The mass of the K accounts for about 37% of the mass of KNO3. So NO3 is 63% of the mass.

    ppm is Mg/L. 100 g in 500 ml is thus 200 000 Mg/L of KNO3 or 12 600 ppm NO3.

    5 ml of this in 600 L would be:
    (0.005 L x 12 600 Mg/L)/600 L = 1 ppm

    So, adding 5 ml of the stock solution to 600 L would increase the NO3 concentration by 1 ppm. If you want to add 10 ppm per day that means you need to add 50 ml of the solution ASSUMING that the plants will use 10 ppm per day. They may use more, they may use less... The only way is to experiment.

    Since you have discus which are heavy and messy feeders you should have no shortage of phosphate in your tank. Don't bother with it unless you see signs of phosphate deficiency. If you test zero it means all the phosphate is in the substrate and that is exactly where you want it to stay.

    Your discus will also produce a lot of nitrate themselves so carefully monitor what is going on.
     
  3. Kryo
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    Kryo Green fingers

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    Thanks Tyrone you're a star!

    Would it be safe to test what the plants take up per day, by doing the following test:

    Day 1 - add 25ml = 5ppm to tank in the morning. Test Nitrate in evening before lights out. Record Result.
    Day 2 - Re-test Nitrate in the morning. Record result.
    Day 3 - Re-test Nitrate in the morning. Record result.

    Over 3 days I can then do a calc to work out consumption per day and how much to dose? I will also record how much I feed the fish over those days and what, so that I get an idea of what their nutrient production is like.... :scratch:

    Is the above test a viable one or did I get too much sun today?
     
  4. Slagter
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    Slagter Aquascaper

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    That is assuming that you have an accurate test kit...

    But remember that the more the plants grow, the more you would have to dose. So yes, your results would be an indication in the beginning, it will slowly become inaccurate as the tank matures.

    One more thing, you should stick to the dosing over the 3 days, and check the levels in the beginning and the end of each day to accurately measure the results. Then average the results to work out consumption over x amount of days.
     
  5. Kryo
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    Kryo Green fingers

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    Thanks Sean.

    Yes that's basically what I intend doing. You see the tricky part with this as well is that I don't really have plants that take up most of their nutrients from their stems. I have plants that are mostly root feeders. I just want to work out a starting point and then monitor things from there.

    The tank has been running since Thursday last week officially and the glosso I planted as teeny tiny cuttings deep into the sand, is growing like crazy but vertically. I did research earlier and there is conflicting threads of info. Some say its light, some say its CO2, some say it's nitrates, some say it's flow, some say a combination of some or all those factors.

    - I have 300w of MH 8000k light over this tank, so light is not the problem.
    - I have loads of flow in the tank and can see the glosso waving in it.
    - I have 5bps of CO2 and the CO2 drop checker is a nice lime green.
    - I have zero nitrates. So this is the only thing I think I need to get cracking on...
     
  6. karele
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    karele Algae harvester

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    To add to the mix I have read that mowing it down after the third or fourth trim it starts to send out runners, who knows :/
     
  7. Kryo
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    Kryo Green fingers

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    Yeah just read that one now actually.

    So on top of all the above I'm going to trim it and replant it. Like planting 400 of the suckers in the beginning wasn't enough blooming work! :BangHead: :laughing7: :laughing7:
     
  8. tyronegenade
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    tyronegenade Specialist

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    Add a large dose so you have about 20-30 ppm (not so good for the discus) and measure daily there-after. My 250 L tank would consume 10 ppm Nitrate in one day. To get a good handle on nitrate consumption you need to know if it is in excess and what rate it is being used at when in excess. As the concentration drops the plants will not be able to use it as fast so you will get in accurate results. If you want to maintain about 10 ppm you need to add more than that and figure out how much you will need to add to maintain 10 ppm, not how fast 10 ppm gets used up. To maintain 10 ppm you may need to dose to obtain 25 ppm at the morning measurement.

    If you find that the plants are using a lot of N and to meet this need means making you discus uncomfortable in a high N environment then you need to reduce your light input as this will slow N use by slowing plant growth. As long as CO2 etc... remain stable the plants will not mind this.
     
  9. Kryo
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    Kryo Green fingers

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    Got it! :thumbsup: I've had my Discus at 20ppm before and they have been fine as long as the food keeps coming! LOL! Will do the tests and then return here to report back. Its a good experiment for people to try I think... Thanks again!
     

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