Does GFO add iron?

[five.five-six]

Just tested for iron with a read sea pro colors kit and it tested 0 iron, I’m running a bunch of GFO, so that seems odd . I do have a small chaeto patch but a reading of 0 is quite unexpected.

 

[Randy Holmes-Farley Verified Community Expert]

You should typically test zero as no kit or hobby ICP method can detect NSW levels.

I do think GFO adds iron, but I dosed it as well.

I could theoretically detect it by Triton ICP right after dosing, but not after a few days of depletion.

A copy and paste of mine:

Iron (Fe). The natural iron level varies a lot with depth, but surface seawater may have only 0.006 µg/L. The Triton LOD = 0.3 µg/L. I dose iron, and when I dose it I boost iron to roughly 1-2 µg/L, which would be detectable. This sample was taken more than a week after the last iron dosing, and none was detected as it gets depleted in the meanwhile. I’ve not yet seen a Triton test result for a real aquarium sample that had detectable iron, but that doesn’t mean these tanks are necessarily deficient. Iron is also a case where the form is critical, and ICP cannot distinguish form. Binding to organic matter, for example, can alter the bioavailability of iron.

 

[five.five-six]

My chaeto is growing well, is that a good metric to gauge iron deficentcy? If I were to dose iron, what would be a good starting point for an immature 135 gallon SPS tank? Mostly frags grown out to 2-3” mini colonies.

The Red Sea kit claims to measure levels of 0, 0.05, 0.15, 0.25, 0.35 and 0.5 if true, would that be a useful test?

 

[Randy Holmes-Farley Verified Community Expert]

My chaeto is growing well, is that a good metric to gauge iron deficentcy? If I were to dose iron, what would be a good starting point for an immature 135 gallon SPS tank? Mostly frags grown out to 2-3” mini colonies.

The Red Sea kit claims to measure levels of 0, 0.05, 0.15, 0.25, 0.35 and 0.5 if true, would that be a useful test?

I personally would not dose enough to detect with that or any kit. The range is too high (IMO).

Trial and error is one reasonable way to see if more iron is useful (actually, I don't know of any other, really).

Here's a DIY recipe:
Buy Fergon iron tablets from the drug store.
Put one pill in about 25 mL fresh water (volume is not that important since dose is not that important for iron). Let it soak for a while or overnight until the tablet breaks apart.

Swirl it to mix. Let is settle overnight. Then use the clear greenish liquid.

Dose about 1 mL per 100 gallons once a week (dose is not critical).

 

[five.five-six]

I don' see fergon. I do see another brand 27mg ferrous citrate.

 

[Randy Holmes-Farley Verified Community Expert]

I don' see fergon. I do see another brand 27mg ferrous citrate.

I picked Fergon based on the other ingredients in the tablet too, but other brands can be ok. [emoji3]

 

[Miami Reef]

I do think GFO adds iron, but I dosed it as well.

Does GFO continuously release iron, or is it only initially?

If I have GFO continuously flowing in a reactor for 2 weeks, would it still be releasing iron?

 

[Reefahholic]

You should typically test zero as no kit or hobby ICP method can detect NSW levels.

I do think GFO adds iron, but I dosed it as well.

I could theoretically detect it by Triton ICP right after dosing, but not after a few days of depletion.

Iron is consumed rapidly in most systems and is commonly depleted w/o supplemental dosing especially if Macro’s are being utilized.

The OP asked…does GFO add Iron?

It’s possible depending on the brand, but iron will be quickly depleted along with other trace elements depending on how much GFO is used or how aggressively in most growing systems.


I think it’s really smart to dose it.

This is why some salt companies boost this element 40-60x+ the normal level.

 

[Reefahholic]

Does GFO continuously release iron, or is it only initially?

If I have GFO continuously flowing in a reactor for 2 weeks, would it still be releasing iron?

It can release all it wants…won’t be much!! Hopefully it is releasing iron, because it’s always depleted in about every growing system, and people chase the dosing for months trying to get it up into target range.

 

[SDchris]

Does GFO continuously release iron, or is it only initially?

If I have GFO continuously flowing in a reactor for 2 weeks, would it still be releasing iron?

I have only used it a couple times.
I like to run the GFO reactor outlet directly in front of the skimmer intake. Always the skimmate turns a darker colour with a more funky smell during use. This continues, but at a reduced appearance/smell over time of use.
There are also small GFO particles on the bottom of the display. Again it's constant but at a reduced rate over time.

I once tried adding some to a coke bottle, shaking a few times, flushing, repeat. 70 times later there was still a discolouration to the water.

 

[Randy Holmes-Farley Verified Community Expert]

Does GFO continuously release iron, or is it only initially?

If I have GFO continuously flowing in a reactor for 2 weeks, would it still be releasing iron?

I expect it is faster at first then gradually slower and slower as the GFO has released the most poorly bound iron ions and also gets covered with other stuff.

 

[Miami Reef]

I expect it is faster at first then gradually slower and slower as the GFO has released the most poorly bound iron ions and also gets covered with other stuff.

Thanks!

Would Ozone increase the ability for GFO to release iron? I have the GFO post the Ozone Skimmer.

 

[Randy Holmes-Farley Verified Community Expert]

Thanks!

Would Ozone increase the ability for GFO to release iron? I have the GFO post the Ozone Skimmer.

I don’t know, but I would guess not. It will have an impact both on organics and on the iron itself.

 

[Miami Reef]

I don’t know, but I would guess not. It will have an impact both on organics and on the iron itself.

Thank you, Dr. Holmes-Farley!

I’m hopefully making an article tonight about the best way (IMO) to mix sodium hydroxide for reef tanks. It involves a secret ingredient: refrigerated RO/DI water.

I tried it with partially frozen water last batch, and it remained very cold even after adding the NaOH. Tonight I’ll test it with plain, cold water.

This should help many people!

 

[Randy Holmes-Farley Verified Community Expert]

Thank you, Dr. Holmes-Farley!

I’m hopefully making an article tonight about the best way (IMO) to mix sodium hydroxide for reef tanks. It involves a secret ingredient: refrigerated RO/DI water.

I tried it with partially frozen water last batch, and it remained very cold even after adding the NaOH. Tonight I’ll test it with plain, cold water.

This should help many people!

Sounds good!