How many dose iron and in what form?
- Thread starter Louis Z
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Plantbrain
Active member
DTPA Fe is about the best chelator for Fe in a marine tank, there's also EDDHA, but it's might red and a tiny bit will discolor the tank's water.
DTPA is sold as Sequestrene 330, about 50 for 5 lbs, which is enough Fe for a mine tank, likely for you, and your kid's life span.
If you want to pay for water, with a tiny bit of ferts in a bottle with a brand name, knock yourselves out
Gluconate and ETDA will not last long and will end up in the sediment as bound Fe, not bioavailable likely in a few minutes.
These are about the least useful forms of Fe for marine systems. If they come in contact fast, within minutes, they will get some, but likely not most of what you dose.
The pH/Alkalinity targeted range for those are about 6.0(under 50 ppm for Alk), the pH range for DTPA is about 7.5 or thereabouts and maybe 100-300 ppm for Alk.
So DTPA will stay in solution longer and have a longer "dose"/contact time with the intended plant or algae.
ETDA is often used, but it's because it's cheap and frankly I just think most of the vendors selling it for marine systems just do not know any better.
That said, it is just a trace, while required for growth, you do not need much. So dosing various chelators or lignands are not going to make huge differences, but you will not need to dose as much DTPA and it cost will be next to nothing over a decade.
DTPA is sold as Sequestrene 330, about 50 for 5 lbs, which is enough Fe for a mine tank, likely for you, and your kid's life span.
If you want to pay for water, with a tiny bit of ferts in a bottle with a brand name, knock yourselves out
Gluconate and ETDA will not last long and will end up in the sediment as bound Fe, not bioavailable likely in a few minutes.
These are about the least useful forms of Fe for marine systems. If they come in contact fast, within minutes, they will get some, but likely not most of what you dose.
The pH/Alkalinity targeted range for those are about 6.0(under 50 ppm for Alk), the pH range for DTPA is about 7.5 or thereabouts and maybe 100-300 ppm for Alk.
So DTPA will stay in solution longer and have a longer "dose"/contact time with the intended plant or algae.
ETDA is often used, but it's because it's cheap and frankly I just think most of the vendors selling it for marine systems just do not know any better.
That said, it is just a trace, while required for growth, you do not need much. So dosing various chelators or lignands are not going to make huge differences, but you will not need to dose as much DTPA and it cost will be next to nothing over a decade.
Plantbrain
Active member
This does not contain bioavailabe Fe, it's fired clay.
If you have strong reduction in the sediment, then you might have a little, but generally, it's pretty inert, same for Carbisea and most of the others, the softer clay like sediments, ADA, UP Aqua, top soils, Worm castings, clay loams, rice paddy soils etc, these have a fair amount of Fe, maybe a decade or more worth. etc
The marine clay loams from Walt Smith or Miracle mud, estuary loams etc, these are pretty good also. We tested a fair amoutn from a wide range of locations and the Fe test for Seachem was done 15 years ago I suppose now by Jamie Johnson(search APD and his name).
While containing Fe in the elemental form, this does not in any way imply bioavailability anymore than does SiO2, glass............offers you oxygen.
Vendors will take such large leaps in the story to sell you stuff.
The iron rich substrate is on the bottom of a 12" DSB. I set tank up 18 months ago to be a marine planted tank. I have found macro so varied, I have not pursued a marine planted tank.
It never gets boring.
Patrick
Don Quixote
New member
I doubt one would ever see bioavailability on the packaging :lol2:
I prefer dosing dry ferts for price/longevity. Feeding unfortunately can't always cover the entire nutrient spectrum. If you have any local Grow stores they can usually special order some for you.
The Don
Plantbrain
Active member
http://www.ebay.com/itm/SEQUESTRENE-330-FE-CHELATED-IRON-10-QUICK-GREEN-5-LBS-/320449799266
Nutrient dosing calculator for DTPA Fe:
http://rota.la/
Use "DIY" for fertilizers.
Then scroll to get DTPA 10%
Chose dry ferts or solution(solution is likely better for Reef/Macro folks)
Use "what to dose to hit a target"
0.2 ppm 2x a week is plenty for most macro tanks.
Nutrient dosing calculator for DTPA Fe:
http://rota.la/
Use "DIY" for fertilizers.
Then scroll to get DTPA 10%
Chose dry ferts or solution(solution is likely better for Reef/Macro folks)
Use "what to dose to hit a target"
0.2 ppm 2x a week is plenty for most macro tanks.
Plantbrain
Active member
Sell the teenager. Keep the six year old.
1/2lb DTPA:
http://greenleafaquariums.com/aquarium-fertilizers-supplements/iron-chelate.html
1/2lb DTPA:
http://greenleafaquariums.com/aquarium-fertilizers-supplements/iron-chelate.html
Plantbrain,
Thank you for your thoughtful posts. I was wondering if you could put some metrics around your DPTA vs. Gluconate/ETDA considerations. Is DPTA twice as effective, three times as effective, etc.? I've been dosing ferrous gluconate (purebulk.com) to spike my iron...
Thanks in advance,
Bob
Thank you for your thoughtful posts. I was wondering if you could put some metrics around your DPTA vs. Gluconate/ETDA considerations. Is DPTA twice as effective, three times as effective, etc.? I've been dosing ferrous gluconate (purebulk.com) to spike my iron...
Thanks in advance,
Bob
Plantbrain
Active member
I think it would pretty hard to quantify the differences, but...we can hypothesize that the DTPA will stay in solution much longer, thus be available longer as a "dose". Mangroves and seagrasses are really the only things with roots in marine sediments. A few inter tidal weeds and bushes etc. Maybe some marine algae with rhizoids, not sure.
But we all know that foliar, blade, thallus uptake occurs for ALL autotrophes.
And the water column will mix slowly within the sediment pore water also.
But if you add something that rapidly precipitates out, it's not going to dose much.
I think the ocean Fe studies used ETDA, but it was cheap and they needed a lot of it. DTPA likely would have done a better job.
I had a graph showing the effective pH ranges for each, but it's dependent more on the alkalinity really, than the pH directly, eg, I can change the pH over 1-2 full units using CO2 gas, but this will have no effect on whether the Fe will stay in solution better/longer. CO2 is not a salt, it'll(dosing it) have no impact on Alkalinity or TDS. Well, 0.25% effect, so small it's not worth mentioning/non significant for us.
But we all know that foliar, blade, thallus uptake occurs for ALL autotrophes.
And the water column will mix slowly within the sediment pore water also.
But if you add something that rapidly precipitates out, it's not going to dose much.
I think the ocean Fe studies used ETDA, but it was cheap and they needed a lot of it. DTPA likely would have done a better job.
I had a graph showing the effective pH ranges for each, but it's dependent more on the alkalinity really, than the pH directly, eg, I can change the pH over 1-2 full units using CO2 gas, but this will have no effect on whether the Fe will stay in solution better/longer. CO2 is not a salt, it'll(dosing it) have no impact on Alkalinity or TDS. Well, 0.25% effect, so small it's not worth mentioning/non significant for us.
Thanks for the details on iron availability. In Febuary, my water well at 550' went dry. I am now in a different zone at 850'. I suspect that I will have to start dosing iron for my macro grow out systems.
Patrick
Plantbrain
Active member
You likely only need about 1/2 what the ETDA suggest. Corals will certainly be helped and anything photosynthetic.
While the DTPA will last longer, it's takes a small bit more energy to take it across the plant, algae membrane. But.....because Fe is not a huge % of biomass, the difference in likely not significant in any way.
So I suppose you could dose a lot of ETDA and more frequently, or just dose less DTPA and not need to mess with more frequent dosing.
You'll just waste a bit more ETDA Fe than you might for the DTPA.
I use hot tap water, then add 10 mls of acetic acid 5% distilled white vinegar to 500mls of water. Shake for a minute, then add the DTPA(say 3 teaspoons).
If you get any fungus etc, you can add Excel(seachem) or potassium sorbate etc. Some use 9 M HCL (muriatic acid), about 10-20mls instead of vinegar.
Vinegar will destroy the alkalinity(Carbonate hardness in this case) and pickle the water so few things can live.
While the DTPA will last longer, it's takes a small bit more energy to take it across the plant, algae membrane. But.....because Fe is not a huge % of biomass, the difference in likely not significant in any way.
So I suppose you could dose a lot of ETDA and more frequently, or just dose less DTPA and not need to mess with more frequent dosing.
You'll just waste a bit more ETDA Fe than you might for the DTPA.
I use hot tap water, then add 10 mls of acetic acid 5% distilled white vinegar to 500mls of water. Shake for a minute, then add the DTPA(say 3 teaspoons).
If you get any fungus etc, you can add Excel(seachem) or potassium sorbate etc. Some use 9 M HCL (muriatic acid), about 10-20mls instead of vinegar.
Vinegar will destroy the alkalinity(Carbonate hardness in this case) and pickle the water so few things can live.
Plantbrain
Active member
Citrate is an extremely weak bond compared to say ETDA and DTPA, which is why we typically use it for vitamins etc, same for gluconate etc.
You can take it on an empty stomach for that reason.
You can certainly use it, or ETDA etc, but I suspect a lot will not target the plants/algae you want to target.
there's a trade off between a weak and strong chelator: takes more energy to break the bond to use the Fe, but if it's all knock out of solution due to a high Alk, not much good either, so if you dosed a lot of of it, it should still give + benefits.
But.....you'd only need maybe 10% of the DTPA.
You can take it on an empty stomach for that reason.
You can certainly use it, or ETDA etc, but I suspect a lot will not target the plants/algae you want to target.
there's a trade off between a weak and strong chelator: takes more energy to break the bond to use the Fe, but if it's all knock out of solution due to a high Alk, not much good either, so if you dosed a lot of of it, it should still give + benefits.
But.....you'd only need maybe 10% of the DTPA.
Plantbrain
Active member
No, this is not true UNLESS you have reducing conditions inside the reactor media.
The precipitation and re-solubility is governed by the reduction potential.
Once the CEC sites are filled, the GFO will no longer bind PO4.
It does not imply that Fe will be released in soluble form.
PO4 can leach back into the system is the GFO media becomes reductive as well.
How much?
This depends mostly on the amount of reduction, the total amount of PO4 bound(or Fe or both) and diffusion in/out of the media/sediment etc.
If the GFO gets neglected for long periods, is not exchanged/recharged, there's ample carbon loading(reduced organic carbon/food waste etc), then that can occur I suppose. Seems rather unlikely, but aquarist neglecting equipment sure does not
So a simple solution is to maintain stuff.
Which is the main thing anyhow.
Water changes, so darn simple, but Reef folks have spent a long time avoiding it and complicating things. Larger reefs, then it's worth it since water changes can add up to a lot of $.
I've often wondered about budgeting salt cost vs all the other stuff to avoid the water changes.
The precipitation and re-solubility is governed by the reduction potential.
Once the CEC sites are filled, the GFO will no longer bind PO4.
It does not imply that Fe will be released in soluble form.
PO4 can leach back into the system is the GFO media becomes reductive as well.
How much?
This depends mostly on the amount of reduction, the total amount of PO4 bound(or Fe or both) and diffusion in/out of the media/sediment etc.
If the GFO gets neglected for long periods, is not exchanged/recharged, there's ample carbon loading(reduced organic carbon/food waste etc), then that can occur I suppose. Seems rather unlikely, but aquarist neglecting equipment sure does not
So a simple solution is to maintain stuff.
Which is the main thing anyhow.
Water changes, so darn simple, but Reef folks have spent a long time avoiding it and complicating things. Larger reefs, then it's worth it since water changes can add up to a lot of $.
I've often wondered about budgeting salt cost vs all the other stuff to avoid the water changes.
Seakrait
New member
Follow up question. Do you think the salt mixes for reefs have enough iron in them to support a macro tank just with weekly water changes? I am able to keep my alk and calcium at acceptable levels by using a salt with elevated numbers and doing weekly to bi weekly water changes. I have reasoned that iodine mg and other important elements would go as the ca and alk go. I should be testing for mg though.
