# Iron & coloration of water



## Costa (13 Oct 2017)

Hello all

I prepared a diy iron supplement by adding 50g of Fe EDTA in 500mL RO. Of that solution I added 15mL into my 900L tank.

Problem is that the iron colored the water red and it's slowly discoloring if course but it still is redish. Is this normal, it did I screw it up?


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## Daveslaney (13 Oct 2017)

50g is alot for 500ml. Normal mix APFUK FE is 2 tsp per 500ml so around 10g.
I would say your mix is way to strong. Where did you get the figures from? What fe you using?


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## ceg4048 (14 Oct 2017)

Costa said:


> Hello all
> 
> I prepared a diy iron supplement by adding 50g of Fe EDTA in 500mL RO. Of that solution I added 15mL into my 900L tank.
> 
> Problem is that the iron colored the water red and it's slowly discoloring if course but it still is redish. Is this normal, it did I screw it up?


It's best not to get too hung up on Iron. Plants don't need nearly as much Iron as they do Nitrogen, Carbon or Potassium. Even  so, it does not really matter if you add too much. It's more a matter of economics. If you are already adding a regular micronutrient mix there is no reason to spend more money for an Iron mix, especially on a tank that size.

The fact that the water turns the water red means that the Iron being used is Ferric Iron (Fe+3) which has a very low solubility and the reason the water has cleared is more likely because the particles have fallen to the substrate and is also being captured by the filter. The solubility can be improved by lowering the pH, which does happen with CO2 addition.

A more soluble form of Iron will be found in micronutrient mixes using Ferrous Iron (Fe+2) which has a much higher solubility and typically has a green color.
The higher solubility of this form of Iron is more efficient from the plants point of view because that higher solubility allows it to be absorbed by the leaves.

Cheers,


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## Konsa (14 Oct 2017)

Hi 
U have spend the money on the Iron suplement already.
There is an option to convert your Ferric Fe to Ferrous using some E300 (Ascorbic asid )
I use it in my all in one mixes and it turns my solution green.It is available from TCN website.
Regards Konsa


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## Costa (14 Oct 2017)

Thank you Clive, Konsa for taking the time to reply, very helpful! There water hadn't cleared this morning either so I did an 80% water change and added only trace mix, which as you are suggesting should suffice.


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## dw1305 (14 Oct 2017)

Hi all,





ceg4048 said:


> The fact that the water turns the water red means that the Iron being used is Ferric Iron (Fe+3) which has a very low solubility and the reason the water has cleared is more likely because the particles have fallen to the substrate and is also being captured by the filter.


I think the red colour is  ferric iron (III) oxide as well. 

Is the stock solution red? or does it turn red in the tank?

cheers Darrel


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## Costa (15 Oct 2017)

Thanks Darrel,
Thank solution is dark red in the bottle too.


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## GHNelson (15 Oct 2017)

Should be about 5grams per 500ml of water!.....


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## Daveslaney (15 Oct 2017)

As you have already mixed you may as well dose it just at lower volumes ie dose 3 or 4ml not 15.


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## dw1305 (15 Oct 2017)

Hi all, 





Konsa said:


> There is an option to convert your Ferric Fe to Ferrous using some E300 (Ascorbic acid) I use it in my all in one mixes and it turns my solution green.


Try acidiifying it. 





Daveslaney said:


> As you have already mixed you may as well dose it just at lower volumes ie dose 3 or 4ml not 15.


I'd try that as well. How much of it will go into solution is going to depend upon the pH and hardness of the tank water. 

cheers Darrel


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## ceg4048 (16 Oct 2017)

Konsa said:


> Hi
> U have spend the money on the Iron suplement already.
> There is an option to convert your Ferric Fe to Ferrous using some E300 (Ascorbic asid )
> I use it in my all in one mixes and it turns my solution green.It is available from TCN website.


Which is a perfect example of throwing good money after bad.
So you actually spend money buying Vitamin C just so you can convert your Ferric Iron to Ferrous Iron?
Then, as Darrel points out, when you add it to the tank, if the pH and hardness are high, it may convert back to it's Ferric form.

I would like to clarify how we are being ripped off:

The red Iron product you have purchased? Well, as Darrel quite rightly points out, it is likely Ferric Oxide.

Here is a typical example of Ferric Oxide:




 

Yes, that's right. The fancy iron supplement contains the active ingredient which can be found on iron nails that you left out in the rain last month. 
It's exactly the same stuff.

I would definitely NOT spend more money on rust. 
If you want to acidify your rusty solution then use any acid that you already have in your kitchen cupboard. 
How about lemon, lime or orange juice, which are all  full of vitamin C (Ascorbic acid)? 
Vinegar (ascetic acid) will work as well.
If you have any type of de-scaler, Like Killrock, for example, then that will most likely be an acid as well, such as Formic acid.

Do yourself a favor and save your money. Next time, just buy a micronutrient mix that is 13% or more in Ferrous Iron.
It will look something like this and will be perfect:


 

If you ever feel as if you need more Iron, then simply add more. 
Why buy another source of Iron when you already have it in the mix you are using?

Cheers,


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