# [Wet Thumb Forum]-Chelated fertilizers



## Nebur (Aug 12, 2004)

EDTA is a common and easy to get anticoagulant, so if I add EDTA to Zinc or Mn or other mineral will it chelate it (I know it does with Ca, Pb and other heavy metals), EDTA is a white concentrated powder, what concentration should I use ?


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## Nebur (Aug 12, 2004)

EDTA is a common and easy to get anticoagulant, so if I add EDTA to Zinc or Mn or other mineral will it chelate it (I know it does with Ca, Pb and other heavy metals), EDTA is a white concentrated powder, what concentration should I use ?


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## MarcinB (Apr 16, 2004)

Yes, EDTA easily chelate Mn and Zn. Every molecule of EDTA can bind one atom of metal, so you need to add one mole (plus few percent extra) of EDTA for every mole of metal.

150L (40G) planted tank
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## Nebur (Aug 12, 2004)

Wow that was a fast answer, do you now what other chemicals (fertilizers)can be bind this way


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## JLudwig (Feb 16, 2004)

Not sure that it is that easy or that you want to do this... The point of chelating something is to hold the chemical in a specific oxidation state, so you need to obtain these salts the way you would like them chelated and make sure they don't oxidize on you. For example, it is my understanding that the Fe 2+ --> Fe 3+ reaction is very fast, I dunno if this needs to be done under vacuum or something fancy like that. Do plants need Mn/Zn in a reduced form? I have no idea.

Why not just buy a hydroponic micronutrient mix, you can be pretty sure it will work, you are not going to save money making your own. How in the world are you going to dose something in the part-per-billion level?? These metals can become toxic in high enough concentrations, and I'm not sure a hobbyist could measure "high enough"...

Jeff


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## MarcinB (Apr 16, 2004)

You can also use EDTA to chelate Fe and Cu, for other micro/macro nutrients chelating agents are not needed.

150L (40G) planted tank
click here for photo
Rate my tank!


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## Nebur (Aug 12, 2004)

Thank you, by the way you can dose in parts per billion, just weight your stuff carefully and add water (you can get 1 part per million or even less), that will be your stock solution, then take a part of it (1 ml for example) of it and dilute it again (1 ml in 1 liter of pure water) another question what do you consider as a billion how many "0"'s
There are lab pippetes that can measure 2 µl (that's 1/1000 of a mililiter) and are not that expensive, if you want to try it is posible, I have plants and fish as a hobby so sometimes I like to do things in the difficult way just for fun.
thanks again


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## Nebur (Aug 12, 2004)

And for MarcinB:
I notice problems with my bannana plant, the leaves were becoming yellow and then transparent, veins were green, so I look for this in a deficiency table and found that manganese could be a cause, reading a little bit more and also said that an excess of Iron blocks the Manganese intake (and this sound a lot more logic), after doing a parcial water change I cut the amount of iron by half (original PMDD) reduced fertilizing to only once a week, lets see the results. So this is a case of toxicity (man induced)as you were looking in some other post


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## MarcinB (Apr 16, 2004)

Thanks Ruben. How much of iron (ppm per week)did you dose before and after?

150L (40G) planted tank
click here for photo
Rate my tank!


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## Nebur (Aug 12, 2004)

To be honest I'm not sure, I bought the chelated and forgot to ask for the formula (I bought 1 kg from a 50 kg container).
I was dosing 7 ml daily and put 9 grams of chelates in 500 ml of ro water
I 've dosing like this since last November
I have to go back to the store and ask, I'll have that information soon


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## MarcinB (Apr 16, 2004)

What chelating agent was used in this fertilizer? What's the size of your tank?

150L (40G) planted tank
click here for photo
Rate my tank!


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## Nebur (Aug 12, 2004)

The agent is EDTA, the iron concentration is 7%, and i was using 9 g of this in 300 ml of water, 7 ml of the mix to my 250 lts tank, so it was something close to 100 mg/week, I ignore the plants extraction rate, do you now it, my only option to Fe test kits is limited to azoo products, I tested their PO4 using known concentrations and it worked OK.


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