What are your iron levels?

Nubbs01 · Mar 14, 2018

I wanted to start dosing iron to see if it will help the growth in my ATS. However I do not believe on dosing anything that I can not test. Therefore I purchased the Hanna Iron LR checker.

For any of you that dose iron and test would you mind sharing your levels? Also please share if you have any information on correlation to levels vs good algae growth.

Thanks!

Randy Holmes-Farley · Mar 14, 2018

Most people do not attain high enough iron levels to detect. Even right after I dosed iron, that checker would not detect the levels I dosed. NSW are far lower than it can detect. So companies selling supplements and test kits (Red Sea) recommend levels high enough for their kit to detect, but I'm not sure why. Perhaps only so their kit seems to have a use. lol

Here's my comment from my article on my Triton results

http://www.reefedition.com/my-triton-testing-results-by-randy-holmes-farley/

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.

Here's a more lengthy article on iron:

Chemistry And The Aquarium: Iron In A Reef Tank ? Advanced Aquarist | Aquarist Magazine and Blog
http://www.advancedaquarist.com/issues/aug2002/chem.htm

Chemistry And The Aquarium: Iron: A Look At Organisms Other Than Macroalgae ? Advanced Aquarist | Aquarist Magazine and Blog
http://www.advancedaquarist.com/issues/oct2002/chem.htm

Nubbs01 · Mar 16, 2018

I appreciate the reading!

Just to make sure I am understanding things right 1 µg/L is micrograms per liter and that is equivalent to 1 ppb correct?

Randy Holmes-Farley · Mar 16, 2018

Nubbs01 said:
I appreciate the reading!

Just to make sure I am understanding things right 1 µg/L is micrograms per liter and that is equivalent to 1 ppb correct?

Yes, at least very close. In seawater 1 L weighs more than 1 kg (unlike fresh water), so 1 ppb = 1 ug/kg = 1.026 ug/L

Nubbs01 · Mar 18, 2018

Well if you are willing then I could use some help with the math just so I know I understand:

I dissolved 1 Fergon tablet into a cup of RODI water and let it sit overnight.

I then tested my tank with the Hanna Iron LR checker and got 0.

The Hanna iron LR checker has you mix a packet with 25ml of sample. In order to test the dissolved fergon tablet I added .1ml of the Fergon dilution to 25ml of RODI water and ran the test several times.

I got an average result of 446ppb. And adding .1ml to a 25ml I diluted it 250 times. Therefore my fergon dilution should be 111,500ppb

With a stated accuracy of plus or minus 20ppb on the checker that puts the range of the dilution from 106,500ppb to 116,500ppb

My system is a 200gallon total water system. This equates to a 757000ml.

If I add one ml of the solution I divided 757000 by both the high and low (106,500 & 116,500)

I get 6.4 to 7.1

So by this math I believe by dosing 1ml of the Fergon dilution I would be at 6.4 to 7.1 ppb in my system.

Is the math correct?

Thanks for your help!
Jason

Randy Holmes-Farley · Mar 18, 2018

You didn't need to test it, but you got the right value for the Fergon, but divided backwards at the tank dosing. :D

One Fergon tablet contains 27 mg of iron.

27 mg in a cup of water (237 mL) gives a concentration of 114 ug/mL, or 114,000 ug/L (ppb).

If you dose 1 mL of this solution into 200 gallons (757,000 mL), you are boosting iron by 114,000 ug/757,000 L = 0.15 ug/L :)

taricha · Mar 31, 2018

I just got my Hanna low range Iron hi746 in yesterday. (Hanna says "not recommended for Saltwater Aquariums" btw)
Took it for a spin today.
I dose Iron from a freshwater plant fertilizer occasionally - if I calc'd right I dosed ~40ppb into my system 14 days ago - and often dose live phyto 50ml a day grown with an F/2 mix that has (??ppb) Iron. But I grow/export a lot of macroalgae. So my actual Iron level could be literally anything from something on the order of 40ppb to nothing.

hanna meter measured 14ppb Fe from my tank water. Stated accuracy is+-20ppb / +-5% so if I understand, that reading should be interpreted as "maybe or maybe not anything"
added 0.10 ml of the FW plant fert that claimed to be 0.10% Fe to 500mL of tank water, (by my math that's 200ppb) and the test showed 207ppb.
Anyway, I'll watch it and see how long it takes to deplete from measurably not zero to within uncertainty of zero and let it ride for a while after that to see if the growth of anything is affected. I have had times when a dose of the plant fert caused what I perceived as a jump in macro/diatom/cyano growth.

Randy Holmes-Farley · Mar 31, 2018

FWIW, that’s a very large dose. It’s a hundred times more than I typically dosed. Here’s a copy and paste of an earlier comment 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.

Tmmste · Mar 31, 2018

Nubbs01 said:
I wanted to start dosing iron to see if it will help the growth in my ATS. However I do not believe on dosing anything that I can not test. Therefore I purchased the Hanna Iron LR checker.

For any of you that dose iron and test would you mind sharing your levels? Also please share if you have any information on correlation to levels vs good algae growth.

Thanks!

Have a look at Fe-EDDHA and Mn-EDTA. I experiment with this for my diy ATS. Growing well..

taricha · Mar 31, 2018

Randy Holmes-Farley said:
FWIW, that’s a very large dose. It’s a hundred times more than I typically dosed. Here’s a copy and paste of an earlier comment 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.

Yep, thanks. I remembered from your article that what I was adding was big, but i had forgotten precisely how big - that everything of interest in reefs is on the scale of 1ppb and way under.

In your opinion, is the Hanna recommendation "not for saltwater" not because there's any issue with the method of testing in salt water in that range, but due to the inappropriateness of that scale (10s and 100s of ppb) for reef tanks.

Randy Holmes-Farley · Mar 31, 2018

taricha said:
Yep, thanks. I remembered from your article that what I was adding was big, but i had forgotten precisely how big - that everything of interest in reefs is on the scale of 1ppb and way under.

In your opinion, is the Hanna recommendation "not for saltwater" not because there's any issue with the method of testing in salt water in that range, but due to the inappropriateness of that scale (10s and 100s of ppb) for reef tanks.

I’m not really sure why they say that, but it could be.

taricha · Jul 11, 2018

bumping this old thing again.
dosing Iron according to Red Sea directions, which is 150ppb as the (absurdly high) target Fe value. This should be well within what Hanna can see, but I wasn't getting numbers that made sense, so I did some beaker tests to look for possible saltwater interference as a culprit. Hanna says "Unfortunately we cannot recommend this for saltwater reef tank testing, only freshwater."
dosed Red Sea Iron+ which claims "1ml/100L raises Fe by 0.01ppm" so 1ml/L gives 1ppm.

All data you see is duplicated, some points are on top of each other. The blue is in freshwater, and the red is in tank water at 35ppt.
It works the same in salt or fresh. So the recommendation to avoid Saltwater use is not based on functioning of the test in SW. It must be due to the inability of the meter for detecting normal sane amounts of Iron (under 1ppb) in tank water.

Now, the other issue, All the tests with Red Sea Iron+ gave me consistently 35% less than they should have according to the guaranteed analysis. The bottle is new - just opened this week.
Weird. So I found another Iron source an ancient bottle of API Leaf zone that is Fe and K. It tested ~50% higher than the label. So I gave up.

I know it doesn't matter how much Fe is actually in a supplement, as long as it's the same order of magnitude it claims, but still it's Puzzling.

I probably trust the hanna meter more than the labels, but if there is an easy way to make a known stock Fe solution I'd like to check it.

Cory · Dec 19, 2020

I know this is an older thread but im curious if the Hanna iron checker is worth it or not?

taricha · Dec 19, 2020

unless you are dosing Iron, you will never have above the limit of detection.
It's a fine kit though. Red sea recommends dosing ~0.1 ppm Fe, which would be easily checkable with this kit.

Randy Holmes-Farley · Dec 21, 2020

I suspect they only recommend levels so high so that their kit can detect it. lol

DeputyDog95 · Oct 16, 2021

So, I decided to go down the ICP rabbit hole, and now I'm trying to "perfect" my tank's parameters...

This is a bit confusing to me, as I've never bothered with iron, especially so with the different metrics to measure it. micrograms, mg, ppb, ppm...

My current ICP reading is: 0.002 mg/L

Is this low? My ICP lap suggests bumping this up to 0.010 - 0.015 (max) mg/l

I am running a chaeto refugium. Does this seem reasonable?

Randy Holmes-Farley · Oct 16, 2021

DeputyDog95 said:
So, I decided to go down the ICP rabbit hole, and now I'm trying to "perfect" my tank's parameters...

This is a bit confusing to me, as I've never bothered with iron, especially so with the different metrics to measure it. micrograms, mg, ppb, ppm...

My current ICP reading is: 0.002 mg/L

Is this low? My ICP lap suggests bumping this up to 0.010 - 0.015 (max) mg/l

I am running a chaeto refugium. Does this seem reasonable?

Any nonzero reading by ICP is not low. ICP cannot detect natural seawater surface iron levels. But dosing it is also fine.

Here's my comment from my own ICP testing:

http://www.reefedition.com/my-triton-testing-results-by-randy-holmes-farley/
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.

DeputyDog95 · Oct 16, 2021

Randy Holmes-Farley said:
Any nonzero reading by ICP is not low. ICP cannot detect natural seawater surface iron levels. But dosing it is also fine.

Here's my comment from my own ICP testing:

http://www.reefedition.com/my-triton-testing-results-by-randy-holmes-farley/
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.