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testing fe/trace levels

Discussion in 'Talk to Tom Barr' started by cazandchris, Feb 28, 2007.

  1. cazandchris

    cazandchris Subscriber

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    when testing to see if I'm reaching the target level for fe do I do so immediately after dosing or should the levels be 0.5 to1ppm at end of week prior to 50% water change. For that mater are all the other target levels pre or post water change
     
  2. Tom Barr

    Tom Barr Founder
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    I do not think there is a residual etc or even a amount to give that really addresses how much. Test kits are very poor in the area of trace metals like Fe.

    The closest way to do this is to add say 5mls per 75 liters 3-4x week, that's the max amount you will need.

    Slowly lower from there, say 3x a week, then perhaps 2x a week with lower light.

    Some divide it up into daily dosing.
    So say you have a 75 liter tank, adding a total of 15mls per week.

    15/7= about 2-3 mls daily.

    If you prefer less frequency: 3x a week x 5mls.

    What you do not want to do in a higher growth CO2/Excel enriched tank: add 15mls after the water for the entire week.

    That's okay, actually about 5mls for a non CO2 tank, but not CO2 planted tanks.

    The test kit issue goes like this: does not test for the bioavailable fraction, it drops out of solution very rapidly(Say seachem flourish, TMG is better) within hours.
    So it does not last long and is certainly not stable over a one day time frame. ETDA chelators are even worse.

    So the argument becomes how much we add and have in solution at any one time is not important. what is important are the plant's health, thus there is little/no correlation between plant health and residual Fe levels.

    Note, we do not test for all the other traces either, we merely use Fe as proxy for all the other trace metals etc, so we may as well use the plant health method.

    Regards,
    Tom Barr
     
  3. cazandchris

    cazandchris Subscriber

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    fe dosing

    thanks tom. when you say 15 mls per 75 ltr.As per your EI light suggestion for mixing 1Tbs of Dry trace mix to 250 mls then 20mls is equivalent to quarter of a tsp then my 150ltr tank needs 30mill/week?Am I correct? Would this be the same concentration as you are suggesting.
     
  4. cazandchris

    cazandchris Subscriber

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    dosing Fe/trace

    I live in Australia and am trying Rexolin APN which is recomended by many here..Just checking if this is the concentration of liquid trace that you are recomending
     
  5. Tom Barr

    Tom Barr Founder
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    That's 15mls per dose for a 75 gallon tank.

    If the tank is 75 liters, then you dose 3x a week, 5 mls each time.
    Yes, the brand you have is likely about the same level for your purposes.
    Try and get some TMG if possible.
    Someone there carries Tropica I'm sure.

    Regards,
    Tom Barr
     
  6. cazandchris

    cazandchris Subscriber

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    TMG or Tropica

    I've checked around and can't find TMG or Tropica. How does Seachem Flourish rate?So far I've been dosing 1/8th of a teaspoon of Rexolin APN 3 times a week for my 150ltr with 3w/g of lighting and Co2. I think thats equivalent to 10mls 3x /week. Am I correct? I have also added the Rexolin breakdown for you to comment on if you don't mind.

    Rexolin APN
    Chelate Trace Element Mix
    Rexolin APN mix contains quality chelate forms of trace elements. It also contains Boron and Molybdenum as salts. Rexolin APN has been developed for the hydroponic industry, however it can be used in fertigation mixes for a wide range of crops. It has high solubility and can be used for foliar and soil applications.
    Available in quantities from 1 kg to 25 kg's
    Elements ratios:
    Iron DTPA 6%; Manganese EDTA 2.4%; Boron 1.1%
    Zinc EDTA 1.3%; Copper EDTA 0.25;
    Molybdenum 0.25%; Cobalt EDTA 0.03% )
     
  7. Tom Barr

    Tom Barr Founder
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    Actually it looks pretty good. Bit rich in B, Mn, Zn for aquatic plants.

    I'd stick with that and add some GH booster and that should take care of things.
    Should be cheap also and better than CMS.

    Regards,
    Tom Barr
     
  8. cazandchris

    cazandchris Subscriber

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    rexolin

    Thanks Tom. Is it ok to use Epsom salts 1/4 tsp / 20g at water change time or should I use a name brand GH booster.
     
  9. Tom Barr

    Tom Barr Founder
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    Yes, a GH booster is CaSO4/MgSO4/FeSO4/MnSO4 and K2SO4.

    So you are adding only one part.
    You most likely would be fine, but if you sprinkle a little K2SO4 and MgSO4 in with the traces, that ought to help some. That's about right for most Mg demands, although adding it a few times a week may work a tad better, hard to say with any certainty in practical tank applications. So 1/8th tsp 2x a week may be a little better, but very hard to say.


    Regards,
    Tom Barr
     

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