Fe(II)citrate

[Tmmste]

I noticed this recipe from randy holmes:

"I selected a dose of about 0.1 to 0.3 mL of a solution containing 5 g of iron (as 25 g of ferrous sulfate heptahydrate) in 250 mL of water containing 50.7 g of sodium citrate dihydrate"

Question 1: I wondered if I can also use sodium citrate trihydrate, and if so, how this will change the recipe. Unfortunately, I am unable to find dihydrate.
Question 2: I would like to mix some iron with my top off water, would it be possible to just add sodium citrate to e.g. 30 liters of topoff water and then add the approporate amount of iron? Or would it be better to first make the solution and then add a certain amount to the top-off water?
Question 3: If question 2 is possible, is it then also possible to add x amount of Mn-EDTA to this?
Question 4: If question 2 is possible, can I also add vinegar and/or ascorbic acid and/or sodium citrate to my top off water

Sorry for all the questions, but I would like to make a solution which is good for several things: dose iron/mn, bind po4, dose carbon

 

[Tmmste]

Basically, I am looking for a way to use Fe for binding with PO4 determined by the level of chelation.. or maybe use only some hydrochloric acid (muriatic acid?) if no3 is already low and you only want to dose iron to bind PO4.. I think it would be nice to know how the level of chelation and iron concentration impacts po4 and Fe levels.

 

[Randy Holmes-Farley]

I've moved to recommending Fergon tablet (ferrous gluconate) for an iron DIY which does everything the iron citrate does, except if you exactly want citrate instead of gluconate.

For the Mn, are you using Mn++ or Mn+++?

You can mix them, but the EDTA may jump over to the iron or, especially, any Fe+++ present.
EDTA binds Fe++ with about the same strength as it binds Mn++. But those are far, far weaker than they strength of its bonds to Fe+++ or Mn+++.

When highly diluted in top off water, the materials will be more prone to oxidation and potential precipitation (my iron citrate recipe slowly turned brown for that reason). But you can certainly try to add it that way.

The hydration of the initial sodium citrate won't matter, but adjust the amount to account for it.

As long as you don't wait too long, the order of mixing won't matter.

Vinegar won't change things much (but I personally wouldn't dose it this way as I think daytime only dosing is better).

The ascorbate may become bound in place of some of the citrate. That's not a problem.

 

[Randy Holmes-Farley]

Basically, I am looking for a way to use Fe for binding with PO4 determined by the level of chelation.. or maybe use only some hydrochloric acid (muriatic acid?) if no3 is already low and you only want to dose iron to bind PO4.. I think it would be nice to know how the level of chelation and iron concentration impacts po4 and Fe levels.

I'm not understanding what you are trying to do. You want a weak chelator if you want the iron to shed the chelator and bind phosphate. Don't mix manganese EDTA into the additive if you actually want precipitation. Simple unchelated ferrous sulfate might be best in that regard. At least it would be fast.

 

[Tmmste]

I'm not understanding what you are trying to do. You want a weak chelator if you want the iron to shed the chelator and bind phosphate. Don't mix manganese EDTA into the additive if you actually want precipitation. Simple unchelated ferrous sulfate might be best in that regard. At least it would be fast.

I see, well, maybe there is a way to chelate some Fe and have some unchelated (e.g. if I would use just a little bit of sodium citrate), but I also would like to prevent it from falling out of solution, if I can determine how much chelate is needed to keep Fe chelated, than I can anticipate on the rising po4 and keep it steady without having to add anything additional..

I think it would be wise to first use heavily citrated Fe and see if Fe levels actually rise... or that po4 is dropping.. if the latter does not happen, than I could experiment with only Fe and muriatic acid and see if how much Fe I need to keep my Po4 levels stable with regular feedings. Unfortunately I did not find any cheap gluconate powder in the Netherlands.. it is very expensive.. so therefore I want to make my own solution. I did buy some Fe(II)-bisglycate, but I do not know how effective this is as a trace element.. there is no documentation on this.

 

[Tmmste]

I've moved to recommending Fergon tablet (ferrous gluconate) for an iron DIY which does everything the iron citrate does, except if you exactly want citrate instead of gluconate.

For the Mn, are you using Mn++ or Mn+++?

You can mix them, but the EDTA may jump over to the iron or, especially, any Fe+++ present.
EDTA binds Fe++ with about the same strength as it binds Mn++. But those are far, far weaker than they strength of its bonds to Fe+++ or Mn+++.

When highly diluted in top off water, the materials will be more prone to oxidation and potential precipitation (my iron citrate recipe slowly turned brown for that reason). But you can certainly try to add it that way.

The hydration of the initial sodium citrate won't matter, but adjust the amount to account for it.

As long as you don't wait too long, the order of mixing won't matter.

Vinegar won't change things much (but I personally wouldn't dose it this way as I think daytime only dosing is better).

The ascorbate may become bound in place of some of the citrate. That's not a problem.

I forgot to reply regarding the Mn; I do not know, it is a red liquid.. if it messes things up I will not use it with the topoff water. It is highly concentrated... only 1 drop is enough (= +38ppm per liter.. so enought for my 400l tank for an entire week). Please let me know what you think of my previous post. Kind regards, Tim

 

[Tmmste]

Any idea Randy?

 

[Tmmste]

?

 

[Randy Holmes-Farley]

Any idea Randy?

You mean about iron bisglycinate? I think that’s fine to use. Not an especially strong bond but will help keep it in solution.

 

[Dennis Cartier]

Not to hijack Tmmste's thread, but you mentioned that the Fe++ might jump ship and bind to the acetate in vinegar. When I made a batch of your Fe++ Citrate in the past, I found that after time, I had issues with bacterial incursion and eventually had a layer of bacterial slime form in the solution. When I was reading a study on binding PO4 using Fe, I noticed that they stated that PO4 was more easily bound by Fe++ rather than Fe+++, and the author added a small amount of acid to keep the Fe++ from oxidizing to Fe+++. This gave me an idea, and the next time I made up a batch of your Fe++ Citrate recipe, I used vinegar instead of water. That was over a year ago, and the solution remains bacteria free. It appears to have darkened somewhat, so I am not sure if the oxidization to Fe+++ was actually prevented or only slowed as it still looks lighter than the contaminated batch that had the slime issues.

If the Fe++ would be capable of chelating with acetate, would foregoing the citrate all together and just use vinegar as the chelator still allow for a weakly chelated solution that has a moderate shelf life? I am only interested in the PO4 binding aspects of this and what I am trying to target my alterations to. It sounds like Tmmste may also be leaning towards this application as well.

Dennis

 

[Tmmste]

Not to hijack Tmmste's thread, but you mentioned that the Fe++ might jump ship and bind to the acetate in vinegar. When I made a batch of your Fe++ Citrate in the past, I found that after time, I had issues with bacterial incursion and eventually had a layer of bacterial slime form in the solution. When I was reading a study on binding PO4 using Fe, I noticed that they stated that PO4 was more easily bound by Fe++ rather than Fe+++, and the author added a small amount of acid to keep the Fe++ from oxidizing to Fe+++. This gave me an idea, and the next time I made up a batch of your Fe++ Citrate recipe, I used vinegar instead of water. That was over a year ago, and the solution remains bacteria free. It appears to have darkened somewhat, so I am not sure if the oxidization to Fe+++ was actually prevented or only slowed as it still looks lighter than the contaminated batch that had the slime issues.

If the Fe++ would be capable of chelating with acetate, would foregoing the citrate all together and just use vinegar as the chelator still allow for a weakly chelated solution that has a moderate shelf life? I am only interested in the PO4 binding aspects of this and what I am trying to target my alterations to. It sounds like Tmmste may also be leaning towards this application as well.

Dennis

Please do respond! I would like to do both. I know only muriatic acid + water + iron will be all I need for binding with po4 (someone I know used this for his iron reactor to bind with po4.. also he believed iron would attach to fiberfill (= cheap filterfloss) as he only used this and a sulfur reactor.. he had no skimmer to remove iron. I purchased multiple products to experiment with Fe for both purposes (po4 binding & as a trace element)

 

[Dennis Cartier]

Bump. Randy, would you have any views on the best chelation (if any) for the ferrous sulfate for efficient phosphate binding? What about my idea of just using vinegar alone rather than sodium citrate for chelation?

Dennis

 

[Randy Holmes-Farley]

Not to hijack Tmmste's thread, but you mentioned that the Fe++ might jump ship and bind to the acetate in vinegar. When I made a batch of your Fe++ Citrate in the past, I found that after time, I had issues with bacterial incursion and eventually had a layer of bacterial slime form in the solution.

The bacteria were likely eating the citrate.

[QUOTE="Dennis Cartier, post: 4822740, member: 72879" When I was reading a study on binding PO4 using Fe, I noticed that they stated that PO4 was more easily bound by Fe++ rather than Fe+++, and the author added a small amount of acid to keep the Fe++ from oxidizing to Fe+++. [/QUOTE]

Ferric phosphate is less soluble than ferrous phosphate, so ferric iron is a stronger binder of phosphate. "Better", however, may be based on other things, and the lack of solubility of ferric iron at higher pH is likely a factor, and the acid may simply have kept the ferric iron from precipitating. I do agree that lower pH (down to about 4) reduces the rate of oxidation of ferrous iron with O2:

https://pdfs.semanticscholar.org/f83d/d855e637c2cd9ad1f9e0b2255706cb9d29e3.pdf

 

[Randy Holmes-Farley]

If the Fe++ would be capable of chelating with acetate, would foregoing the citrate all together and just use vinegar as the chelator still allow for a weakly chelated solution that has a moderate shelf life? I am only interested in the PO4 binding aspects of this and what I am trying to target my alterations to. It sounds like Tmmste may also be leaning towards this application as well.

Dennis

Acetate is a very weak binder of iron. Gluconate is far better (hence the Fergon recommendation).

But for phosphate binding, I'm not sure why you want it chelated at all, and ferrous sulfate itself may be fine.

 

[Tmmste]

Acetate is a very weak binder of iron. Gluconate is far better (hence the Fergon recommendation).

But for phosphate binding, I'm not sure why you want it chelated at all, and ferrous sulfate itself may be fine.

Hi Randy, have you ever fried a few ml 30% muriatic acid with ferrous sulfate to for a liter stock solution (to use it as phosphate binder)? I would like to try this soon, when I receive the chemicals I ordered. If the pH is around 4 this should prevent the iron from oxidising? If you never tried this, do you happen to know how many ml muriatic acid 30% I would need to keep the pH that low (for a total solution of 1 liter).

 

[Randy Holmes-Farley]

I've never tried it and I'm not sure it will be useful, but it takes very little and it is easy to overshoot in unbuffered water.

pH 4 means 10-4 moles H+/L.

Concentrated muriatic acid is about 12 M.

So you need to add about 0.008 mL to a liter.

 

[Tmmste]

I've never tried it and I'm not sure it will be useful, but it takes very little and it is easy to overshoot in unbuffered water.

pH 4 means 10-4 moles H+/L.

Concentrated muriatic acid is about 12 M.

So you need to add about 0.008 mL to a liter.

Hi Randy,

I thought i'd just add 5 ml to be safe than sorry. I wanted to make a 40.000ppm solution so I added 200gr iron(II)sulfate hepahydrate (total solution 1 liter).

first I removed around 200ml of water, added 5ml muriatic acid 30% and then added 200gr ijzer sulfate. Shaked it..

However it seems like some iron is falling out of solution. Some brown sediment formed on the bottom.

I wonder if this is due to vigorous shaking or maybe impurities collecting on the bottom?

update:...unfortunately I am unable to test the solution. Last week po4 was 0.3ppm.. I added 3gr iron-bisglycate to my topoff water along with vinegar... I forgot I added the iron so I just tested my po4... it dropped all the way to 0.03 ppm! unbelieveable, I can believe the result.

 

[Tmmste]

@Randy Holmes-Farley I am almost certain this is oxidised iron as I spilt some powder... after removing this with a damp cloth it instantly turned brown. It also smells a lot when it oxidises.. Today the liquid is still green and the layer of Fe(III) on the bottom did not increase.

 

[Randy Holmes-Farley]

What does it smell like?

 

[Tmmste]

What does it smell like?

It reminds me of blood.