Iron test kits

[Petex]

hi,
are there any aquatic Iron test kits out there which measure also chelated Iron like DTPA and EDDHA?
(my test kit doesn´t)

 

[rjordan393]

The Nutrafin Iron test kit will test for chelated iron.

 

[Petex]

How sure are you?
Have you tried to meassure Fe-DTPA/EDDHA with the Nutrafin test?

I ask this, because my iron test kit was also advertised as an iron test kit "that can measure chelated iron".
Fact ist, it still can measure chelated Fe-EDTA (and for some parts Fe-HEDDTA) - but it failures at FE-DTPA & FE-EDDHA.
(and I guess many other test kits will also not detect Fe-EDDHA, Fe-DTPA, Fe-EDDCHA )

 

[rjordan393]

The nutrafin test kit only says it will test for chelated iron and non-chelated. You will need to contact the manufacturer about other forms of iron. I was using edta iron at the time I purchased the kit. Sometimes I use ferrous gluconate but I need to test for it in about 10 minutes after dosing as this will not read on any test kit after about 1/2 hour.
Do you test soon after dosing?

 

[Petex]

Yes, gluconate breaks down very quickly in a tank.
EDTA will last some hours or a little bit longer depending on PH.
DTPA ist more stable and I was told EDDHA "should" last some days.

I am using DTPA/EDDHA in my own fertiliser mix, so I am certainly interested to know how long those iron chelates now really last in the water coloumn and if there is perhaps any accumulation.

 

[rjordan393]

I will see if I can find out on another forum I subscribe to; if no one here has an answer. In the meantime, check out this article on "iron Transformation" which is related to your question. Http://www.skepticalaquarist.com/ferrous-ferric

 

[Petex]

Thank you very much if you would ask on a place where ppl. know such things.

The Test kit i have uses a mix off acetic acid + sodium hydroxide to change the PH from the test solution, so that the iron gets unbound from the chelate - but it hasn´t worked out. Like you can see on this chart, Fe-EDDHA is pretty PH stable and so I guess many test kits may have some serious problems with such strong chelates: http://www.smart-fertilizer.com/loadedFiles/iron chelate.png

 

[rjordan393]

Here is a reply from one of the forum moderators:

From JeffyFunk's water testing results (using a proper machine) we figured out that only EDTA and DTPA chelated iron show up in water samples. Gluconate and citrate chelated iron does not show up at all in his tests. I suspect the same is true for the titration kits you can buy.

I would suggest you contact the manufacturer in Canada for further information. Sorry, I can not help any further. Nutrafin test kits are manufactured by the "Hagen" company.

- - - Updated - - -

Here is a reply from one of the forum moderators:

From JeffyFunk's water testing results (using a proper machine) we figured out that only EDTA and DTPA chelated iron show up in water samples. Gluconate and citrate chelated iron does not show up at all in his tests. I suspect the same is true for the titration kits you can buy.

I would suggest you contact the manufacturer in Canada for further information. Sorry, I can not help any further. Nutrafin test kits are manufactured by the "Hagen" company.

 

[Tom Barr]

Thank you very much if you would ask on a place where ppl. know such things.

The Test kit i have uses a mix off acetic acid + sodium hydroxide to change the PH from the test solution, so that the iron gets unbound from the chelate - but it hasn´t worked out. Like you can see on this chart, Fe-EDDHA is pretty PH stable and so I guess many test kits may have some serious problems with such strong chelates: http://www.smart-fertilizer.com/loadedFiles/iron chelate.png

Yes, you will need something very strong to get the EDDHA out, but few hobbyists use it, it's really super red and only a tiny bit will make your water turn red in color.

DTPA, you should be able to address that with a stronger acid, say HCL or H2SO4. I think Paul K. had some data on the DTPA in solution.

http://fins.actwin.com/aquatic-plants/month.9703/msg00232.html

 

[Tom Barr]

Thank you very much if you would ask on a place where ppl. know such things.

The Test kit i have uses a mix off acetic acid + sodium hydroxide to change the PH from the test solution, so that the iron gets unbound from the chelate - but it hasn´t worked out. Like you can see on this chart, Fe-EDDHA is pretty PH stable and so I guess many test kits may have some serious problems with such strong chelates: http://www.smart-fertilizer.com/loadedFiles/iron chelate.png

Yes, you will need something very strong to get the EDDHA out, but few hobbyists use it, it's really super red and only a tiny bit will make your water turn red in color.

DTPA, you should be able to address that with a stronger acid, say HCL or H2SO4. I think Paul K. had some data on the DTPA in solution.

http://fins.actwin.com/aquatic-plants/month.9703/msg00232.html

 

[Petex]

@robert
thank you for asking.

@Tom
The Fe-EDDHa part isn´t huge, because too much will discolour the water pinkish.
I still use around 5% - 10% EDDHA or so, the Fe-DTPA part is higher around 30%. The other 70% are Fe-EDTA / HEdDTa and I am also playing a little bit around with ferrous gluconate.
For Fe-DTPA it seems I found an austrian test kit which can meassure it.
So still the EDDHA thing is left.

 

[Tom Barr]

I'd just leave the EDDHA out entirely, use the Gluconate instead.
You plan on doing more than once a week etc?
Do not have an insanely high KH?

Then do not bother with it.

 

[Tom Barr]

I'd just leave the EDDHA out entirely, use the Gluconate instead.
You plan on doing more than once a week etc?
Do not have an insanely high KH?

Then do not bother with it.

 

[Petex]

The KH isn´t high, but I need to pump lots of ferrous gluconate iron in my highlight tanks, let say 0,3-0,5ppm/day and doing so will be expensive in the long run.
50-100g Ferrous gluconate cost in Germany around $60-80 and this seems not to be the best price deal if 100g Fe-EDDHA, Fe-DTPA and similar stuff, cost less then $10.

 

[Tom Barr]

The KH isn´t high, but I need to pump lots of ferrous gluconate iron in my highlight tanks, let say 0,3-0,5ppm/day and doing so will be expensive in the long run.
50-100g Ferrous gluconate cost in Germany around $60-80 and this seems not to be the best price deal if 100g Fe-EDDHA, Fe-DTPA and similar stuff, cost less then $10.

Yikes, that's a lot o Euros.
You might try Fe gluconate from bulk vitamin suppliers, they tend to be much cheaper.

http://purebulk.com/ferrous-gluconate-powder.html#.UxdPkT-wLYg

Buy 3 kilos and you will have enough for a few years.

 

[Tom Barr]

The KH isn´t high, but I need to pump lots of ferrous gluconate iron in my highlight tanks, let say 0,3-0,5ppm/day and doing so will be expensive in the long run.
50-100g Ferrous gluconate cost in Germany around $60-80 and this seems not to be the best price deal if 100g Fe-EDDHA, Fe-DTPA and similar stuff, cost less then $10.

Yikes, that's a lot o Euros.
You might try Fe gluconate from bulk vitamin suppliers, they tend to be much cheaper.

http://purebulk.com/ferrous-gluconate-powder.html#.UxdPkT-wLYg

Buy 3 kilos and you will have enough for a few years.

 

[Petex]

wow, thats pretty cheap.
I still guess they wont ship outside USA? Even if they would, I fear the UPS shipping will be very expensive and in Germany you need to pay high taxes at customs offices for any imported articles (outside EU).
Only if buying inside EU, there are no taxes.