FE EDDHA

Discussion in 'Aquarium Fert Dosing' started by Craig Matthews, 15 Apr 2019.

  1. Craig Matthews

    Craig Matthews Member

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    I have very hard water so I'm needing to dose Fe eddha but as I've read it tints the water red. I'm thinking to not mix it in my ei micro mix but add seperately on micro day. Do I add a tiny amount so the water does not turn red or should it turn slightly red indicating that there is enough? Will the red tint fade as it's uptaken by the plants or constantly be there,
    Thanks
     
  2. dw1305

    dw1305 Expert

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  3. Zeus.

    Zeus. Member

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    Bet we have the same water supply Criag so same issue :rolleyes:. I have added Fe DTPA to my micro mix and light sheilded all the piping and then add Fe EDDTA manually on Micro ferts day whilst I work out what dose works before I commit to adding it to the micro mix. The tank can get very red if you dose to 0.5ppm which was compounded as I had Glowlux T5 tubes ( Glowlux have a high red output in the red spectrum which makes the pink tinge stand out more IMO) on at the time which I have swapped for some 6500K T5 tubes I had already and not as bad. After WC the tank is lovely and clear.
    Yes it does seem to clear as the week goes on a little but the Fe DTPA in my micro mix does seem to recharge the Fe EDDTA tinge a little
    I have considered using RO water and mixing 50;50 to resolve the issue but would need a big storage tank for my 200-300litre WC. Can get the RO water locally at £0.06p per litre

    Heres what it looked like just before WC 9had just done a massive trim and mini rescape of some plants - end view if 1.5m long tank
    upload_2019-4-15_12-59-26.png

    Tank had been dosed 0.3ppm Fe DTPA and about 0.1ppm Fe EDDTA this week


    compared with Fe EDDHA weekly dose of 0.6ppm with growlux tubes on
    upload_2019-4-15_13-2-58.png

    In my 50L tank the pink tinge isnt as bad as the tank has less width and depth OFC
    Plants looking better in both tanks IMO
     
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  4. Craig Matthews

    Craig Matthews Member

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    Ok thanks Darrell
     
  5. Craig Matthews

    Craig Matthews Member

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    I bet we have the same supply it's super hard 127mg/l calcium my micro mix will be EDTA so it doesn't have an effect, I out some eddha in my micro mix bottle and added to some sample water and wow it's red. I have the fluval 2.0 led light.i have no idea how to measure the iron content as I've read in here the tests are not even accurate so it's pointless? I was thinking of just adding a pinch straight to the tank until it turns slightly red/pink but if I'm doing this every micro day I'm assuming it will stay pink? I was thinking about ro water to it's very cheap but the hassle of lugging big drums about is abit off putting.
     
  6. dw1305

    dw1305 Expert

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    Hi all,
    You can't easily test for iron (Fe) ions in the water, if you were a water company you would use <"ICP-MS">.
    Yes I'd just add a pinch, and when you can't see any pink tinge add another pinch, plants don't need a lot of iron. The problem with very hard water is that there aren't any iron ions available, all the iron is combined into insoluble compounds and none of it is plant available.
    @Zeus.'s is the really important point, it doesn't seem very scientific but it works, just watch the plants. Scientists do this, they just call it a "bioassay".

    The main thing to note is that because iron isn't mobile within the plant you will get a lag period before <"new non-iron deficient growth"> occurs.

    cheers Darrel
     
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  7. Craig Matthews

    Craig Matthews Member

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    Thanks Darrell I'll do the bioassay and see how it goes over the next couple of weeks with the pinch method im sure my problem is hard water causing insoluble iron, I've also been adding 1 tea spoon if magnesium daily as old leaves if helferi yellow then die off I think it's a mixture of both elements
     
  8. Craig Matthews

    Craig Matthews Member

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    Thanks Darrell I'll do the bioassay and see how it goes over the next couple of weeks with the pinch method im sure my problem is hard water causing insoluble iron, I've also been adding 1 tea spoon if magnesium daily as old leaves if helferi yellow then die off I think it's a mixture of both elements
     
  9. Craig Matthews

    Craig Matthews Member

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    Zeus to be fair the pictures don't look to bad, I could probably live with that especially because I have black phantoms,barbs and pristella tetra they would probably benefit. Lovely tank as well mate
     
  10. Zeus.

    Zeus. Member

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    Here a pic just taken after 50-60%WC yesterday my EI macro mix then today with auto doser it was dosed my Micro mix with Fe DTPA 0.1ppm
    upload_2019-4-15_17-46-35.png

    I then dosed Fe EDDTA manually 0.05ppm when I got home

    upload_2019-4-15_17-48-36.png

    So as you can see the Fe DTPA @ 0.1ppm is no notable difference but the Fe EDDTA @ 0.05ppm extra does go pink.

    So depends on what your target Fe ppm dose to how pink it goes. Plus bigger tanks go more pink for same ppm dose

    You could go down the Fe DTPA route -
    Fe chelated by DTPA: min 10.5%
    Practical pH stability range: 4 – 7.5 (in aqueous solution).

    Well I am in the early weeks/months of using it, so just trying to see what works myself, but it does seem to fade then I dose some more OFC - I am probably dosing too much as its the EI way of things. But think finding the dose that works and dose it every micro ferts day is the best option, then once you find what works just add Fe EDDTA to your normal Micro dose to hit the Fe EDDTA tank ppm that works - well thats my plan

    Good question about the PO4 and I am unsure of the correct answer - Maybe @dw1305 or @Oldguy or someone else could answer better than me!
     
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  11. Craig Matthews

    Craig Matthews Member

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    Hmm very Interested to find out if all this makes a difference, I'm a newbie to all this higher rachy of elements so I'm pretty naive to how it all works. I read iron tests are not accurate how are getting your readings for iron ppm Zeus or is there a mathematical matrix solution?
     
  12. Zeus.

    Zeus. Member

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    Me too still finding my feet and lots to learn ;)

    Yep Rotala Butterfly select the volumes and ppm

    upload_2019-4-15_20-32-51.png

    So a 10ml dose to my 500L tank yields 0.1ppm Fe - so for every 1ml of stock solution I add I add 0.01ppm Fe in 500l tank and one tenth the dose for 50l tank

    but I use Fe eddha (7%) not Fe eddha (6%) as above but Fe eddha (7%) not on list so I use Fe DTPA (7%) calculation below for amount to add to 1 litre and its in the right order IMO
    upload_2019-4-15_20-36-57.png

    So 71g of Fe EDDHA (7%) to 1 litre of water

    then I used excel and few spreadsheets bit of maths. Plus the data sheets from the products I got from solufeed checked the maths all seem in the right order, recheck recheck the maths
     
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  13. dw1305

    dw1305 Expert

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    Hi all,
    You know how much iron (in ppm = mg/L) you've added from the percentage of iron in the compound (6% for FeEDDHA), how many grams you've added and the volume of the aquarium. You can use one of the <"online calculators">, if you aren't confident about your calculations.

    The availability of a nutrient depends on it staying in solution as ions, plants can only take up nutrients as ions from solution. Some compounds are always soluble, so when you add potassium nitrate (KNO3) you know that all the K+ and NO3- ions you've added are in solution and available to the plant, but it isn't like that with iron (or phosphorus (P)) compounds, most of them are insoluble.

    So basically you can add as much iron chloride (FeCl3.6H2O) as you like, but it doesn't supply much plant available iron, because as soon as it dissolves the Fe+++ ions will find other anions (PO4---, OH-, HCO3- etc.) in solution and precipitate out as solid compounds, which are unavailable to the plant. The plant only has a very brief window of opportunity before the iron ionbs are mopped up and become solid precipitates.

    When we use a chelator, like EDTA or EDDHA, the iron is bound in a complex organic acid, which means that it is unavailable to form other compounds, and also unavailable to the plant. If we keep the chelator in the dark this is how things remain, but FEEDTA is degraded by light which allows a trickle of iron ions (Fe+++) to be released into the aquarium.

    cheers Darrel
     
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  14. Oldguy

    Oldguy Member

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    It's all a bit of a compromise. If the transition metal ions are too strongly chelated they will not be available to plants but as simple ions they tend to precipitate out of solution and again become unavailable to plants. The EI dosing regime of macros and micro nutrients on alternate days tries to minimize these effects. There is however another important factor that is the replacement of the chelated trace element (as an ion) by other metal ions. This replacement competition can be reduced if all the transition metal ions are chelated but there will also be Mg and Ca ions present in the tank water which can displace your chelated trace metal ions. The jockeying for position is dependent on concentration of competing ions and the pH of the tank water with regard to the chelating agent being used. Iron ions have about a 24hr half life in typical fish tank waters as soluble salts.

    The chelating ligands are also typically photo-degraded. This and ion replacement produce a slow release of transition metal ions as simple salts for plant utilization. [It is possible with heavy handed application of the chelating agent to mobilize metals out from plant tissue and into solution].

    Unfortunately most of the data in the public domain and of research interest is focused on hydroponic or horticultural, especially foliar feeds for fruit crops, applications.

    The stuff we buy from our LFS is derived from such data and generalized to one size fits all and profit maximized to make a niche market worth playing in. It is always worth remembering that the bottle is the most expensive bit in production and water, if it is an aqueous product, the most abundant component.

    Well worth following @Zeus with his trials. Excellent tank Zeus keep up the posts, we watch with interest. We also watch as the market moves to supply the more specialist reagents. God Bless the Internet.
     
    Last edited: 16 Apr 2019
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  15. Zeus.

    Zeus. Member

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    So how is the Fe in FE-EDDHA released I asked myself :bookworm:

    Understanding of the Mode of Action of FeIII–EDDHA as Iron
    Quote
    The very low reduction potential of the chelate FeIII–EDDHA (EDDHA= ethylenediamine N,N′‐bis(2‐hydroxy)phenylacetic acid) makes it unreactive in photochemically or chemically induced electron transfer processes. The lack of reactivity of this complex toward light invalidates photodegradation as an alternative mechanism for environmental elimination. However, in spite of its low reduction potential, the biological reduction of FeIII–EDDHA is very effective. Based on electrochemical measurements, it is proposed that FeIII–EDDHA itself is not the substrate of the enzyme ferric chelate reductase. Likely, at the more acidic pH in the vicinity of the roots, the ferric chelate in a closed form (FeL−) could generate a vacant coordination site that leads to an open hexacoordinate species (FeHL) where the reduction of the metal by the enzyme takes place.
    Unquote

    So from above it is proposed the FeEDDHA is biological reduced by the plants roots to free the Fe for uptake

    IRON CHELATE INTERFERENCE: THE DOWNSIDE OF FE-EDDHA AND FE-HBED - quote Fe-DTPA is a great iron chelate product, but it exhibits rapid photodegredation. One study reported a half life of 30 minutes in full sunlight. When I used Fe-DTPA, I found my iron levels would drop from 2.5ppm to 0.0ppm within 3 days unquote so fast photodegredation for FeDTPA - so this makes me think should I dose my Micro mix with FeDTPA in it in one dump or multiple ? multiple for the photoperiod seems to be the obvious answer to me and easy to do with PLC so three equal doses two hours apart from lights on done ;)

    Iron Sources in Hydroponics : Which One is the Best ? another interesting read

    Yep but you use the tools/papers on hand



     
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  16. Oldguy

    Oldguy Member

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    Yes we do and like you do empirical trials and note the results. It's an age old conundrum is it Science, Technology or Engineering that take the lead in development. We can but try and as the Saxon proverb goes 'We must row with the oars that we have.'

    Research, think (twice), do and evaluate. The cycle of progress.

    I use EDTA as my tank water is suitable and use alternative day dosing and assume photo degradation and central ion replacement by GpII ions to release Fe ions. No precipitation of iron and no obvious shrimp deaths from Cu. Used to have a useful contact at Allied Colloids which made a range of chelated compounds which I played around with but that was a different time.
     
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  17. Oldguy

    Oldguy Member

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    I would go for multiple small doses. A 30 min half life is short.

    To what extent are the roots of aquatic plants comparable to those of terrestrial plants for nutrient uptake. Also would the iron complex diffuse through the substrate at a fast enough rate. I go back to my earlier point that much of our information is from hydroponics and hence terrestrial plant growth.
     
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  18. dw1305

    dw1305 Expert

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    Hi all,
    That is interesting.

    The question would then be what happens in hydroponics, (and for floating plants), can they still generate reducing conditions in the rhizosphere? and make the Fe++ ions available? If FeEDDHA works as an iron source in hydroponics it would suggest that they can (or possibly there is another mechanism that makes the iron ions (FE++(+)) available?). I can see that @Oldguy has just asked the same questions, so I'm going to assume that I'm on the right track.

    I know a lot of the work on the biochemical mechanisms of iron uptake in roots was done using Limnobium, I'll see which iron sources they used.

    I must admit I had just assumed it was photodegradation, I didn't check.
    It should give you a slight increase in iron availability, I'm not sure that would relate to an increase in growth, mainly because of the low requirement of plants for iron, "some" is usually "enough".

    cheers Darrel
     
    Last edited: 17 Apr 2019
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  19. dw1305

    dw1305 Expert

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    Hi all,
    I think the iron reduction would occur within the rhizosphere, so with very little spatial separation from the root. Roots are leaky structures, and plants can use these exudates both for direct uptake of ions and to alter the microbial assemblage to their advantage.
    Because roots can only take up nutrients as ions from solution I suspect that there isn't really much difference, what may differ is the associated microbial assemblage. My guess is that this is where a lot of the current research effort is targeted.

    I've just down-loaded <"Sampling root exudates – Mission impossible?"> which may have some of the answers.
    Looks like <"Evidence for the Uptake of Non-Essential Ions and Essential Nutrient Ions by Root Hairs and Their Effect on Root Hair Development"> is the reference I want, it says (however this was using Tomato):

    FeRootHair.JPG

    cheers Darrel
     
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  20. Zeus.

    Zeus. Member

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    Yes. But the half life of 30 mins was from full sunlight. I have slight the daily dose to 3 doses ATM as was easy to do, but do plan to design a Logo PLC software that will dose the daily dose equally in multiple doses every 30mins, Just need to design it should be straight farward @ian_m might even get it done before I get time as he is quick at it ;)
     

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