Dosing Fe & Mn recommandations

[Tmmste]

I wondered if anyone has a recommended dose for Fe and Mn (safe dose per liter aquariumwater in ppm). I am thinking about using Fe-EDDHA and a combination of manganese + trisodium citrate + vodka.

Would 0,0002 ppm (0,2 ppb) Mn and 0,00014 ppm (0,14 ppb) Fe be a good starting point (per liter aquariumwater)?

I do not know if a small amount of the chelated iron will remain stable in a large amount of water though.. the same goes for manganese. Else I will make it much more concentrated (like dosing a 0,1 ml for 100 gallons containing the total recommended dose)

 

[Randy Holmes-Farley]

This is my DIY iron dose using Fergon tablets from a drug store:

Take 1 tablet and dissolve in 100 mL RO/DI (overnight soak). Let the solids settle out and use the liquid. Then I dose about 1-5 mL to my 200 gallons (dose is not critical) occasionally.

One tablet is 27 mg iron, so that dose comes to about 0.3 to 1.4 mg.

Put into 200 gallons, that's about 0.4 to 1.8 ppb.

 

[Randy Holmes-Farley]

I'm not sure how fast manganese is depleted. With no dosing, my triton test showed none, but they can barely detect the NSW level (around 0.17 ppb), so I'm uncertain how much of a dose might be useful.

But I would not dose more than 0.17 ppb once or twice a month without monitoring.

 

[Tmmste]

This is my DIY iron dose using Fergon tablets from a drug store:

Take 1 tablet and dissolve in 100 mL RO/DI (overnight soak). Let the solids settle out and use the liquid. Then I dose about 1-5 mL to my 200 gallons (dose is not critical) occasionally.

One tablet is 27 mg iron, so that dose comes to about 0.3 to 1.4 mg.

Put into 200 gallons, that's about 0.4 to 1.8 ppb.

Dear Randy,

Thank you for your reply Randy. Yes, I have been reading about it. I do wonder what your opinion is on using Fe-EDDHA. It should not oxidise as fast as weaker chelates (like EDTA or citrate), so it should be available for a longer time before it turns into rust and immediately reacts with phosphates. Apart from that 0,2 ppb would be a bit more conservative. I could increase it to 0,4 ppb. However
some shoot for a much higher dosage (0,1 of more ppm). Would this actually benefit the symbiotic algae?

 

[Randy Holmes-Farley]

My concern with higher strength chelates is lack of bioavailability. I'm not sure on that one.

From one of my iron articles:

http://www.advancedaquarist.com/2002/8/chemistry

In many cases of iron intended for the marine hobby, the product may not tell you what the iron is chelated with, in order to protect proprietary formulations. I don't actually know if it matters too much. Very strong chelation by certain molecules will actually inhibit bioavailability by not permitting release of the iron without completely taking apart the chelating molecule, but I expect that manufacturers have avoided those molecules. EDTA and citrate, and some others, actually degrade photochemically, releasing small amounts of free iron continually. It is believed to be the free iron that is actually taken up by many organisms, and likely iron(II), though some organisms may be able to convert iron(III) to iron(II) before uptake (the detailed absorption mechanisms are generally not known). There is a more detailed discussion of this degradation and uptake in "Captive Seawater Fishes" by Stephen Spotte (1992).

 

[Randy Holmes-Farley]

I'm not sure why Red Sea recommends such high iron levels, except perhaps so it can be detected by a kit. I've not actually seen a reported benefit from such high levels.

 

[Tmmste]

My concern with higher strength chelates is lack of bioavailability. I'm not sure on that one.

From one of my iron articles:

http://www.advancedaquarist.com/2002/8/chemistry

In many cases of iron intended for the marine hobby, the product may not tell you what the iron is chelated with, in order to protect proprietary formulations. I don't actually know if it matters too much. Very strong chelation by certain molecules will actually inhibit bioavailability by not permitting release of the iron without completely taking apart the chelating molecule, but I expect that manufacturers have avoided those molecules. EDTA and citrate, and some others, actually degrade photochemically, releasing small amounts of free iron continually. It is believed to be the free iron that is actually taken up by many organisms, and likely iron(II), though some organisms may be able to convert iron(III) to iron(II) before uptake (the detailed absorption mechanisms are generally not known). There is a more detailed discussion of this degradation and uptake in "Captive Seawater Fishes" by Stephen Spotte (1992).

I have been reading a bit about chelates. I noticed this graph, maybe interesting to share. Apart from EDDHA there is also EDDHMA (and HBED.. the most powerfull chelate out there).. I will be trying EDDHA myself. Ofcourse manufacturers will not share their formulations, but that does not stop me from trying myself. Apparently most chelates will fall apart under alkaline environments..

 

[Randy Holmes-Farley]

What is that graph from? I suspect it may not actually relate to our situation.

I suspect that since we all dose massively more than iron levels in NSW surface waters, it won't matter, but I still have a preference for weaker chelates, such as the gluconate in Fergon, since I don't want to hold it back from being taken up, and dosing more often, if needed, is easy.

 

[Tmmste]

What is that graph from? I suspect it may not actually relate to our situation.

I suspect that since we all dose massively more than iron levels in NSW surface waters, it won't matter, but I still have a preference for weaker chelates, such as the gluconate in Fergon, since I don't want to hold it back from being taken up, and dosing more often, if needed, is easy.

I found it here; https://manicbotanix.com/chelates-in-hydroponic-solutions/

I think this may actually be interesting. Some posts on a Dutch forum related to chelate are marked as xxxxx, so I think there is something about it (protecting sponsors) I guess a weak chelate would quickly turn iron into rust and a great liquid phosphate remover.

 

[Randy Holmes-Farley]

Are you using Fe++ or Fe+++?

I think that data is for Fe+++.

 

[Tmmste]

Are you using Fe++ or Fe+++?

I think that data is for Fe+++.

I am not using anything yet, I will be looking for Fe(II) though.. (III = gfo I guess). But the chelate would behave similar I assume. A fellow dutch reefer used to make fe-citrate to reduce phosphates (and switched to acid instead due to bacterial slime). Apart from that I suspect that a certain Dutch "method" also uses a weak chelate for this purpose succesfully. However, for actual supplementation of Fe, he used EDDHA. According to him this worked fine (DPTA was useless in his opinion for this purpose.. so I guess EDTA falls in the same catergory). Unfortunately that is all the information I got from him.

 

[Tmmste]

I have been dosing "Canna Fe+" for some time now (few drops each day), a combination of 50% Fe-EDDHA and 50% Fe-DTPA, so far so good, no negative developments.

 

[Hans-Werner]

The stronger iron chelates are formed with Fe III since this is the smaller ion with the higher charge. Usually the Fe III is reduced to Fe II before uptake which weakens the chelate bond and makes it possible to take up the iron from the decaying chelate. At least the bacterial siderophores work this way.

 

[Tmmste]

The stronger iron chelates are formed with Fe III since this is the smaller ion with the higher charge. Usually the Fe III is reduced to Fe II before uptake which weakens the chelate bond and makes it possible to take up the iron from the decaying chelate. At least the bacterial siderophores work this way.

Thank you for your reply; do you think a different form of chelated iron would be more suitable? (as a trace element).

 

[Tmmste]

Anyone?

 

[Randy Holmes-Farley]

I don't think there is any info on which chelated forms are best, but I personally avoid very strong iron chelators.

In general, we dose iron to values far higher than are actually needed, and even strong ones likely work fine.

 

[Tmmste]

Update:

- Fe-EDDHA dosing thusfar no negative results.

also purchased Mn-EDTA, I will also start dosing this soon.

 

[Randy Holmes-Farley]

Update:

- Fe-EDDHA dosing thusfar no negative results.

also purchased Mn-EDTA, I will also start dosing this soon.

That’s not super enthusiastic to say no negative effects. lol

What about positive effects? [emoji3]

 

[Tmmste]

That’s not super enthusiastic to say no negative effects. lol

What about positive effects? [emoji3]

To be honest, Randy, I am unable to tell. As I run ATS only the algea has been growing fast and corals are doing well. If this is the result of feeding a lot, iron dosing, slightly elevated no3/po4, more plankton/rich water, improved stability, less intense light and clearer water due to calciumcarbonate (diy coralsnow)... I do not know. I do know everything is looking well and EDDHA has not crashed the tank. I also have not seen any ill effects on the animals like fast breathing. The scrubber looks very green.. as long as it is does not turn yellow I would say there is enough iron in the water.

 

[Randy Holmes-Farley]

OK, thanks.