There is speculation that UV lamps do effect iron and other trace minerals in the water column. You could try turning it off just for a day and see if it makes a difference.

 

OK, thanx, I'll try that and inform you in the weekend.

 

I understand that iron never lasts long in an aquarium. People dose, then measure how much iron is there and it is always near zero. I think that is because the plants quickly absorb the iron and store it. Also, if the water contains phosphates, and it should, some of the iron precipitates out, ending up on the substrate instead of in solution with the water. The iron is still available to the plants, but at a slower rate.

 

you're adding what is probably chelated iron, what happens is that soon after you dose the iron it is:

1. absorbed directly by the plants because this form is highly usable by plant mass

2. it joins your substrate as previously mentioned, in one of several methods, one of the common methods is it oxidizes and becomes iron oxide (rust) which may not be detectable using a "iron test kit"

Overall you shouldn't worry about iron deficiency unless you begin to see some very specific iron-related symptoms in your plants. if you're using proper substrate it should contain iron already in addition to what you're adding as a supplement, no harm should come of additional iron supplments (you're just making it easier for your plants)

but be careful adding too much iron or trying to test and see where your iron is going, its probably being converted in a variety of ways into forms that cannot be detected by your test kit.. but this iron still remains available to your plants!

Re: adding iron

is a brief article that adds a little science to the entire iron discussion and supports what is commonly understood in standard landscape/plant keeping.

 

Southpark is right. Iron chemistry in planted tanks isn't as straightforward as nitrate or phosphates. Iron is a heavy metal, and doesn't like to remain in a dissolved state. It's quite chemically active. Most commercial preparations use a chelator (a big molecule which basically grabs onto the iron & doesn't easily let go) to keep it dissolved. By itself it rapidly reacts in the tank to form various oxides. As a rule, these aren't very soluble and it settles out to the substrate.

In the substrate, in the root zone, different chemical reactions take place due to the lower oxygen levels. This returns iron to a form that can be used by plants.

Iron test kits, even the good ones, aren't too useful. Add a good quantity and stop worrying about it unless you're seeing deficiencies in the plants.

Beautiful tank, BTW. The discus look fabulous.

 

Nice tank!

As mentioned, don't worry about the test kit results as long as the plants aren't showing any deficiencies.

However, in terms of cost, you can probably reduce the dosing amounts and still provide enough iron for the plants. 0.4-0.5ppm of Fe per day is quite a bit more than the plants will probably need/use.

I bet that you could easily reduce the amount of Fe you dose by quite a bit and still keep those plants beautiful! Especially with the amount of lighting you have...

And welcome to APC!

 

Hi again everybody...
I did the test this weekend and here are the results. Without using the UV, the iron I measured was almost the same as the previous day. I had added ~0.5 ppm and for the next 3 days I measured 0.4, and 0.25 ppm. Then I added again iron to 0.5 ppm and turned on the UV lamp. In the next 12 hours there was no iron to be measured. I don't know what really happened with the iron... But, for sure, the problem is the UV lamp! And here is my next question: should I use the UV and not fertilize with iron or fertilize with iron and turn off the UV? To be honest I don't want to do either of these. I would like to use the UV 24/7 and also fertilize with iron. But iron is photosensitive. And if so, I suppose that the same thing happens with my flourish excel (which is also photosensitive!). I'd like to mention that I run the same test with Seachem iron too, with the same results.

I really don't know what to do... I'll ask Seachem and wait for your suggestions

P.S. Thank you everybody for your nice words about my tank

 

Out of those choices I'd definitely go for fertilizing with iron and forgetting about the UV. The UV is not helping your plants while the iron is (concentrate on the plants!).

On the other hand I may be biased as I've never used a UV and never saw the need for one...

 

UV light

Use it wen you need it, when algae, or on a par week or month basis.
I don't own a UV light but if you know it oxidize elements like iron you can have a weapon to act when invasion occurs or to prevent any.

OXIDATION; Fe II (Ferrous) available to plant wen oxidize to become Fe III (Ferric) less accessible for plant but can be recombined with chelated agent like Humic acid, fulvic acid and tannic acid are examples on non-contaminant organic complexes. Phosphate also serves as a very effective complexing agent for iron, becoming available again to plant in a somewhat less soluble form than Fe II ferrous.

This an idea for the time it take for Fe2 to oxidized:
At pH 7.0,
90% Fe2 oxidation requires 1 hour at 21 degrees C and
10 hours at 5 degrees C.

At pH 8.0, 90% Fe2 oxidation occurs in 30 seconds,

at pH 6.0 it requires 100 hours.

The critical dissolved oxygen concentration is 2 mg/L. Below that ferrous iron oxidation occurs slowly.

 

I use UV 18W over 400 lt 24/7 my iron is always around 0.1 ppm, most I have ever measured is 0.4 ppm. I use a colorimeter and test measures both Fe2-Fe3
I don't see any iron deficiency in the plants at the moment (by the way sometimes I think it is easy to consider some symptoms as iron defficiency while there are from something else) except if I stop my iron dosing for 3-4 or more days. I use Power4 plus a bit of additional boron which is exactly the same with microplex in usa. So I reckon that as long as you keep up with good iron fertilization you will have absolutely np. By the way I would be very conservative with commercial test result concerning iron. So in my opinion go and use your UV anyway you want and add iron until you see np in your plants, Also bear in mind the interactivity between ferts in relation to the availability of iron as others have mentioned aswell, what this interactions are I have no precise clue.
Freemann

 

I use UV 18W over 400 lt 24/7 my iron is always around 0.1 ppm, most I have ever measured is 0.4 ppm. I use a colorimeter and test measures both Fe2-Fe3

What is your Fe ppm daily dose?

Thanks

 

Edward
I use a trace mix called Power4 it is exactly the same with Microplex containing:
Mg-5.4%
Bo-0.5%
Co-0.05%
Cu-1.5%
Fe-4.0%
Mn-4.0%
Mb-0.1%
Zn-1.5%
On this initially I have added a bit of Boron as per PMDD instructions
I add currently 0.3 gr/day 4-5 times per week (I don't forget).
Today's reading for example for total Fe was 0.08 ppm
I have never read more than 0.24 ppm iron (bear in mind I always added enough iron)
I hope this helps

 

Fe NOT diseapearing...

In fact all the iron you supply do not disappear, is only transforming and do not register on aquarium iron tests.

Look at this article on the web on Iron:
iron

As I say before , in any condition, Iron, rapidly move from is Ferrous (more soluble & available to plant form) to Ferric and these 2 form can be complexed by a ligand that increase their solubility and bioavailability. The iron stay in the system and available until it's absorb by plant, animals, microbe. When your cleaning you tank, Changing water, cutting down plants etc some of the iron go away from the system. It will stay bioavailable until the crystallinity of the ferric iron mineral increases and the microbiological availability decreases to finally form insoluble Iron deposit like hematite or magnetite.

Passing in your UV your Ferrous is transform in Ferric right away but still available by plants but do not read in your normal aquarium test.

 

Freemann,
What is it in ppm of Fe a day?

Thanks

 

Edward
0,03 ppm which thinking of it is not that a huge amount.
. By the way yes it is on the high light aquarium. 4.1 w MH 20 cm from the surface for 6 hours.

 

Colorimeter is a great tool. In order to maintain a steady level of Fe you've been dosing 0.03 ppm a day. This is on your high light aquarium I guess.

Thank you for the info