What trace mix?

Discussion in 'Aquarium Fert Dosing' started by Henrik, 24 Nov 2008.

  1. Henrik

    Henrik Member

    Messages:
    67
    Location:
    Chester, Cheshire
    This got mentioned but then lost in another post, so if I may ask the question in a seperate thread:
    What trace mix would people recommend - I read that the AE mix was OK, but contained a weak chelator (EDTA), and that I should look for HEDDTA or DTPA. Who can help with this, where can I buy the right mix?

    I have still got some Dennerle V30 and ProFito (do they actually conatin better chelators?) - which I will use up before making my own, alongside the dry ferts nutrients I am starting on now. Would you consider the recommended dosages in line with the requirements of a CO2 injected, well-planted, moderately lit (2wpg) tank, or should I add more?

    Thanks, Henrik
     
  2. JamesC

    JamesC Member

    Messages:
    1,276
    Location:
    Bexley, Kent
    AE traces are fine and many people use them with excellent results. Currently if you want to use a decent iron chelator such as HEDDTA you need to buy Tropica's TPN. EDTA can cause problems if you have hard water as it breaks down quite quickly releasing the iron. This free iron then reacts with compounds such as phosphate to create iron (III) phosphate which is insoluble. This is often seen as an orange buildup of within filters and substrates. I find I have this problem which is why I'm looking at alternatives.

    Garden Direct's chelated traces I think use a different chelator as their mix is green in colour. Iron EDTA is red in colour as the iron is in the ferric (3+) state. Ferrous (2+) iron is green in colour. It is possible to change ferric iron into ferrous iron by adding a reducing agent such as ascorbic acid. This is why people who add ascorbic acid to there trace solutions find that the solution turns green.

    Some say that it's only ferrous iron that is available to the plants, but I'm not so convinced. Still, if the iron can be kept chelated longer then more will be availble to the plants.

    As an experiment add some iron sulphate to your tank and watch the PO4 levels drop as the iron reacts with the phosphate, dropping it out of solution into the substrate or filter.

    James
     
  3. GreenNeedle

    GreenNeedle Member

    Messages:
    2,706
    Location:
    Lincoln UK
    Henrik. Put your location in your profile and then people in similar areas will know where you are and will have a rough idea of any problems you may face water wise from their own experiences.

    I use the AE trace and just make up small 100ml mixes (just in case)

    If you are dosing dry then it shouldn't matter I wouldn't have thought

    AC
     
  4. Themuleous

    Themuleous Member

    Messages:
    4,126
    Location:
    Aston, Oxfordshire
    I use the AE trace and its always worked well for me.

    Sam
     
  5. Henrik

    Henrik Member

    Messages:
    67
    Location:
    Chester, Cheshire
    Done.

    Does an UV clarifier break up chelators? I have one which I put on for a few hours at night - not sure whether it is needed, I got it when I was raising discus a few years back.
     
  6. JamesC

    JamesC Member

    Messages:
    1,276
    Location:
    Bexley, Kent
    Yes it does. So does any strong light source.

    James
     
  7. Henrik

    Henrik Member

    Messages:
    67
    Location:
    Chester, Cheshire
    Does that mean UV clarifiers are not recommended for planted aquariums? Or should I run it only once a week, and not dose traces on that day? I never quite figured out what to do with UV clarifying, when I had the discus their well-being came first, but now with less sensitive fish I might give it up in favour of plant performance..?
     
  8. JamesC

    JamesC Member

    Messages:
    1,276
    Location:
    Bexley, Kent
    Give it up. But if you do want to run it then do it during the night and then dose in the morning. Used to be a bit of a heated debate a few years ago. Some people say it makes no difference whilst others say they suffer iron deficiency. I'm on the side of if you don't need it then don't use it.

    James
     
  9. Henrik

    Henrik Member

    Messages:
    67
    Location:
    Chester, Cheshire
    Back to the traces - can anybody help me understand what is the likely composition of traces in 'off the shelf' fertlisers - TPN, ProFito, Dennerle V30 are the ones which I own or have read much about (TPN).

    I have seen James' listing of the composition of TPN+, can we conclude from that what the normal TPN could be? James, you also give the translation from % values into ppm for your DIY TPN+ - how does this conversion work, as I wanted to translate the 'real' TPN+ as well?

    TPN+ seems to be a bit low on Potassium, should I assume other general fertilisers are the same and dose Potassium Sulphate while I am using up my ProFito and Dennerle V30?
     
  10. JamesC

    JamesC Member

    Messages:
    1,276
    Location:
    Bexley, Kent
    Often if you go to the company websites they give you a listing of what's in them. Tropica give a very detailed account. TPN is pretty much the same as TPN+ except TPN+ has added N and P in the form of ammonium nitrate and potassium phosphate.

    48g Potassium Nitrate to 500ml DI water.
    Nitrate weight is 62/101 x 48 = 29.5g
    If 500ml contains 29.5g than 5 ml contains 0.295g KNO3.
    If you add the 0.295 to 50 liters you will have 295mg/50l = 5.9mg/l

    29.5g NO3 to 500ml water
    N weight = 14/62 x 29.5 = 6.66g
    6.66g in 500ml = 6.66/500 x 100 = 1.33% N

    TPN+ isn't low on potassium. My mixture is higher in potassium which shouldn't cause any problems. Most people comment it's a bit low in PO4 but as most peoples tap water has plenty of PO4 it should work well.

    James
     
  11. Henrik

    Henrik Member

    Messages:
    67
    Location:
    Chester, Cheshire
    Great, I have understood the calculation, but I am struggling to find the other molecular/atome weights (which I googled, but all the calculators give me different results for NO3 and N than the ones you provided). Can you help with this?
     
  12. JamesC

    JamesC Member

    Messages:
    1,276
    Location:
    Bexley, Kent
    N=14
    O=16
    NO3 = 14 + (16x3) = 62

    James
     
  13. Henrik

    Henrik Member

    Messages:
    67
    Location:
    Chester, Cheshire
    I got the % right for KNO3 and KH2PO4, but could not work it out for Magnesium Sulphate MgSO4. I googled a bit and found MgSO47H2O as Epsom Salts, and it works when I use the molecular weight of this formula. Do I have to watch out to get Epsom Salt, or is any Magnesium Sulphate on sale delivered in this fomat (e.g. AE's) :? ?

    For the trace mix I figured out that since it is 5g/500ml, I divide the % on Aqua Essentiels website by 100. Got it. Thanks.

    I guess I now know what I need for the aquarium ferts, and how it all hangs together. THANKS a lot for your patience...

    For my hydroponics ferts (slightly off topic, but I would love to cover two needs in one when buying the ferts), the leaflet says that 100g/litre Potassium Nitrate and 40g/litre Magnesium Sulphate deliver 38.2% Potassium and 13.5% Nitrogen NO3-N, as well as 10.0% Magnesium. This is roughly ten times what I calculate from the KNO3 (K at 3.87%, N at 1.39%), but not at all what I get for Magnesium (Mg at 0.39) - are these things expressed differently for regular fertilisers?

    Thanks again, Henrik
     
  14. JamesC

    JamesC Member

    Messages:
    1,276
    Location:
    Bexley, Kent
    Magnesium sulphate is MgSO4.7H20 is epsom salts. Take a look at wikipedia - http://en.wikipedia.org/wiki/Magnesium_sulfate Americans haven't learnt how to spell sulphate yet.

    You have to be careful with other fertilisers as they are often expressed in different ways. Sometimes as ppm NO3 and others as N from NO3, etc.

    James
     
  15. ceg4048

    ceg4048 Expert/Global Moderator Staff Member

    Messages:
    8,953
    Location:
    Chicago, USA
    Sorry, but this is clearly an impossibility. The potassium nitrate molecule KNO3 is the same no matter who sells it and no matter where in the universe it resides. KNO3 has a molecular weight of approximately 101 grams per mole. K has an atomic weight of approximately 39.1 grams per mole. Therefore the K atom comprises approximately 39.1/101, or 38.7% by weight of the KNO3 molecule - always and without exception. It appears you have a decimal point error in your calculations.

    100 grams of KNO3 powder has 38.7 grams of K and 61.3 grams of NO3. N comprises 22.6% of the weight of an NO3 molecule therefore 61.3 grams of NO3 has 13.8 grams of N.

    100 grams of KNO3 dissolved in 10,000 L of water will yield a concentration of 10ppm KNO3. Based on the relative weights above this will yield about 6.1ppm NO3 (of which 1.38ppm is N), and 3.8ppm K.

    Compare this analysis to your data above and you will see that where you have "percentages" it should read ppm. This is the origin of the decimal point error which accounts for the erroneous "10 times" comparison.

    This is also the origin of the misconception regarding Nitrogen concentration due to nitrate. The annotation "N-NO3" concentration is only 22% of the total NO3 concentration. Therefore if data reports 1ppm N-NO3 this really means that the nitrate concentration was actually 1ppm/.22 or about 4.5ppm NO3.

    Cheers,
     
  16. Henrik

    Henrik Member

    Messages:
    67
    Location:
    Chester, Cheshire
    I do not quite understand this. If I dose TPN+ even at double the recommended amount, I do not get to the EI recommended levels of Potassium (10-30ppm). I just about get there with James' recipe, and any higher dosing would make the nitrate go above 30ppm. Have I picked up wrong numbers anywhere?
     
  17. JamesC

    JamesC Member

    Messages:
    1,276
    Location:
    Bexley, Kent
    One of the downsides of using an off the shelf product is that it probably won't deliver exactly what you want. This is why dosing with dry salts is so good. If you want some extra K then add a bit of K2SO4. Some people think TPN+ is a bit lean on PO4 so add a bit of KH2PO4. A lot of people have had great success using just TPN+ so it does work well. It was formulated to use with an average tank that has some PO4 and K already present in the water, as is often the case in Europe.

    James
     
  18. Henrik

    Henrik Member

    Messages:
    67
    Location:
    Chester, Cheshire
    My water board does not supply info on Potassium content in the tap water, they said 'traces' (but they also said that for Calcium and then came back and said it's 34.4ppm!). Any ideas what average tap water figures are in the UK - I am in a soft water area at the North Welsh border.

    Hopefully the last questions in addition to the one above:

    1. When I look at the EasyLife (ProFito) website, they say that their fertilisers contain many additional ingredients that help you grow better plants - and TPN contains another ingredient - ammounium nitrate - that is not listed here. Is this all Marketing talk, or is there something behind it? I am still undecided whether to go for dry traces or a pre-made mix (ProFito or TPN) - clearly for KNO3 and KH2PO4 I will not buy prefabricated liquids again.
    2. Do the dry powders go off - even on KNO3 500g will give me five years supply. KH2PO4 will last for ages!

    Thanks for all the great support, and sorry for asking so many questions. All this was totally new to me, so far all I did was dose some random fertiliser every 2 or 3 weeks or so...which worked well on only a few plants.

    Henrik
     
  19. JamesC

    JamesC Member

    Messages:
    1,276
    Location:
    Bexley, Kent
    Average figures won't be much help as it won't mean anything for you. If your water is very soft then you can buy some Seachem Equilibrium or GH Booster which not only adds Calcium and Magnesium but lots of Potassium as well. Then you can use TPN+ and see how you get on with that. As long as you don't have masses of light I'd thought that would probably work. See how others dose the TPN+ and copy that to start off with. Then if you want later to save some money you can switch to the dry salts.

    Most manufacturer's claims their product has some magic ingredient that makes plants grow better. Actual ingredients aren't normally quoted but component values are. So NH4NO3 is quoted as N.

    Dry powders don't go off as long as you keep them dry.

    James
     
  20. keymaker

    keymaker Member

    Messages:
    255
    Location:
    Budapest, Hungary
    My calculator has all the molecular weights right (taken from James' site) and it's easy to use. Just type in the KNO3 quantity and you'll get the K and NO3 mass instantly...

    My point, exactly. If you have no K in your tap water, not even double TPN+ dose is enough. What I did at first is supplement it with K2SO4, but then some GSA arrived indicating low PO4. That was the point when I decided to ditch TPN+ (luckily, there's not much left) and go for the dry ferts mix.
     

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