# Where does all the iron go?



## ray-the-pilot (May 14, 2008)

OK what ridiculous amounts of iron do you add to your water?

I am following PPS pro. This plan adds the equivalent of 0.1ppm of Fe to my tank a day. 
I have tested my water for Fe using a validated method and find that when I put the required amount of Fe in my tank I will find 0.1 ppm there but after about 24 hours it is gone. 
Where does it go?
My guess is from testing my filter and substrate is that it precipitates out. Both places have lots of Fe after a while.
I guess I am wasting Fe?
Using this plan my plants grow wild and I need to trim back about 100% every 2-3 weeks.
My water is soft and acid (from CO2) and is about 70 ppm in GH.
Alright, for those of you who have run your systems for over a year, how much Fe do you use on a daily basis. If you are able, can you list your daily doses in ppm of Fe per day? Also what is your GH and pH?
Maybe we can come to a consensus of how much Fe is needed.

OK as an edit maybe you can say what form the Fe is in: i.e. EDTA chelate (if you know). 
Mine is as an EDTA chelate.


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## HeyPK (Jan 23, 2004)

One of the commercial Iron chelates used for aquarium plants is gluconate. This is easily digested by germs, and the iron then precipitates out. If it precipitates on the plants, then the plants still may be able to absorb it. Light causes slow precipitation of iron EDTA, but some other chelates, such as DPTA are not precipitated by light. Iron precipitating in the substrate can get recycled when mulm mixed with the precipitate decays in the substrate. The oxygen content is lowered to the point where bacteria start reducing the ferric iron to ferrous iron, which is soluble. The solubilized iron gets back in the water column, where it again precipitates. This gives the plants another chance at utilizing it either in soluble form or as a precipitate on the plant.


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## wet (Nov 24, 2008)

Is your Fe test measuring ferrous iron (Fe +2)?

Iron and heavy metals will go away from the water column in at least two ways: a) biomass/plant matter/fauna, which is good, because those guys need iron to live, and b) oxidation, where it falls out of the water column and into your substrate. In a long term aquarium heavy metals falling out of solution isn't a big deal since biocroters in your substrate will do redox, at which point the iron becomes food to the plants again. 

I do believe folks are just wasting iron with high (0.5 and up) doses. More importantly, if that iron comes from some comprehensive trace mix, I believe they're doing harm by raising the levels of other micronutrients (such as copper, though my experience is just that dosing less of that other stuff makes prettier plants and saves $).

I dose around 0.2 ppm Fe. I do it more often when light/plant uptake is higher, to the point of daily dosing in a healthy tank. I think it is smarter to invest in good chelators that avoid oxidation than it is to use the brute-force approach of lots and lots and lots of dosing. Ultimately, the cost difference of such an investment is like $3/yr or something for most of our tanks.


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## ghostmonk (Jul 6, 2009)

HeyPK said:


> One of the commercial Iron chelates used for aquarium plants is gluconate. This is easily digested by germs, and the iron then precipitates out. If it precipitates on the plants, then the plants still may be able to absorb it. Light causes slow precipitation of iron EDTA, but some other chelates, such as DPTA are not precipitated by light. Iron precipitating in the substrate can get recycled when mulm mixed with the precipitate decays in the substrate. The oxygen content is lowered to the point where bacteria start reducing the ferric iron to ferrous iron, which is soluble. The solubilized iron gets back in the water column, where it again precipitates. This gives the plants another chance at utilizing it either in soluble form or as a precipitate on the plant.


 Even the one that precipitates on the substrate is utilized by plants when it is not in it's soluble form.


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## ray-the-pilot (May 14, 2008)

*HeyPK, wet and ghostmonk!*

Thanks for your input! I am interested in the "theory" of what happens to Fe but I am more interested in facts. By facts, I mean, what do you do? How much Fe do "you" add each day to your tank? How are your plants growing? Can you tell me something about the other parameters in your tank? 
Probably my title was a little misleading. I really want to know how much Fe successful plant growers add to their tank each day.

BTW My test for Fe in the water column measures Fe+2 and Fe+3. I start with approx. 50 ml of tank water and evaporate it to dryness. I oxidize all the carbon residue in air which, also converts any Fe+2 to Fe +3. Then I redissolve the residue in dilute HCl and measure the Fe+3 using a standard method. I am a chemist so I enjoy doing stuff like this.


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## wet (Nov 24, 2008)

ray-the-pilot,

I am interested in usage rates as well, but have posted more than proportionate about Fe and micros in general on various forums (and also above) and so don't think have much to add here. But if you're interested, there's a couple of existing threads out there that might be better to bump. I happen to host some images in these and they get regular traffic. In case you missed them:

Mostly in regards to chelator quality, reasons chelators are important, and then dosing targets. Also the first place afaik that EDDHA has been documented in the aquarium:
http://www.aquaticplantcentral.com/forumapc/fertilizing/67958-chelated-iron-yes-no.html
Fe in context to the other traces via cloning Tropica Master Grow/Plant Nutirition:
http://www.plantedtank.net/forums/f...385-diy-tropica-plant-nutrition-mix-your.html
Plantbrain loves graphs and data for available Fe in the water column:
http://www.barrreport.com/showthread.php/6930-How-long-iron-gluconate-quot-live-quot-in-tank

Adding to the applied aquarium samples/actual amounts dosed in terms of ppm, type (chelator), and frequency to those threads might end up more beneficial, simply because there's already samples of data and existing traffic.

I've considered wiki-izing this somewhere, by the way, and allowing public edits to add more data. Or maybe hariom or another talented designer will tackle it, since oxidation, heavy metals, and toxicity are always popular threads and maybe the last bit of voodoo for folks regarding dosing...


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## ray-the-pilot (May 14, 2008)

wet said:


> ray-the-pilot,
> 
> I am interested in usage rates as well, but have posted more than proportionate about Fe and micros in general on various forums (and also above) and so don't think have much to add here. But if you're interested, there's a couple of existing threads out there that might be better to bump. I happen to host some images in these and they get regular traffic. In case you missed them:
> 
> ...


I went to your links but I was disappointed with what was there. We, I mean you and I and everyone else in this hobby, are not interested in theories about what happens to Fe. We (you and I) are interested in facts. That means, tell me what Fe form you are using and for how long and what do your plants look like. These are facts. If we get a lot together, we can come to some idea about what is a good plan. We don't want any discussion about what we think!

For me (and I've said this many times) growing plants is really easy. I don't know what a deficiency is, my red plants are vibrant red and I throw away the equivalent of a tank load of plants every 2-3 weeks. This is my experience after 2 1/2 years of work.
OK I understand that maybe I am lucky so I'd like to do a survey. It goes something like this:

How long have you been growing plants in an aquarium?
Can you keep and maintain an aquarium with plants in it for at least 3 months without having a major algae break out?
Do you have any deficiency problems?
How much Fe do you dose per day?
What form is the Fe in (Chelated with EDTA, Gluconate, Citrate, etc.)

I don't think this is the perfect questionnaire but you get my point. No BS about toxicity, pH, uptake from precipitated Fe, etc. All of this is just opinion. (which is good) but we need facts.

OK here are my answers to the questions:

How long have you been growing plants in an aquarium? 
2 1/2 years

Can you keep and maintain an aquarium with plants in it for at least 3 months without having a major algae break out? 
Yes easily

Do you have any deficiency problems? 
I have never seen a deficiency

How much Fe do you dose per day? 
0.1 ppm per day

What form is the Fe in (chelated with EDTA, Gluconate, Citrate, etc.). 
Either Fe as an EDTA chelate or as a citrate chelate.

This hobby doesn't need opinions about what to do it needs: "Here is what I did and the results are..."


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## wet (Nov 24, 2008)

I disagree, actually. The process you're describing (one I try to emulate for my own sanity) is great for scientific study and data collection, but it's not how most gardeners operate. For example, I know GGhori, OKnott, and JBaliban tanks and methods pretty well because I am such a fan, but I do not know their target ranges. In the case of most gardeners, I think the method is more "Hey, new growth on my Mayaca/HM/P. Stellatus/whatevs is looking a little pale. Add Iron.". Cavan can grow whatever he wants and operates this way, for example. In fact, I am of the opinion this measurement is much more effective than ppm. 

To put this another way, how many times have you read testimonials from people who claim healthy tanks, no dosing, and argue with convention while avoiding posting pics of their tanks? How many people who can speak in terms of ppm also have documented pictures/proof/plus plants?

(I'm mostly playing devils advocate here and pointing out the absolute data you're looking for isn't absolute at all. Why should i believe your nice plants are really nice? Do you have pics of those plants showing that they've grown nice reds and not inherited reds from trims of another person's aquarium? Without this, how are these data points "fact" or better, how are they more relevant than what you consider conjecture and opinion?

Also, there's an nfrank survey on Fe out there that's worth bumpage.)

Anyway,

How long have you been growing plants in an aquarium?
I started sometime in 2004. 

Can you keep and maintain an aquarium with plants in it for at least 3 months without having a major algae break out?
Sure. I think it's worth mentioning I've broken plenty of tanks via neglect after moving to new jobs or in the middle of fun summers 

Do you have any deficiency problems?
Not when I run the tank to grow stuff instead of goofy experiments. I can definitely grow whatever I want nicely when I want to. 

How much Fe do you dose per day?
In a healthy high-uptake tank, around 0.2ppm Fe. 


What form is the Fe in (Chelated with EDTA, Gluconate, Citrate, etc.)
Today, EDTA and DTPA. Also have dosed with EDDHA, HEEDTA (via Tropica) and whatever is in MicroPlex.


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## barbarossa4122 (Dec 31, 2009)

I dose lots of Iron via Miller, CSM, DTPA, EDDHA and Fe Gluconate as Wet already knows. No algae and my plants are very happy.


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