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60 Posts
Discussion Starter · #1 · (Edited)
I tried to mix my own micro ferts and I am now running (after some weeks dosing) in some problems.

Plants like Ludwigias, Limnophilia are growing fast and dont show much deficieny:

- but my Rotalas are getting dark green leafs and the Didiplis (in the same tank) bends the leafs down:

Nesea Golden looks pretty worst :p :

Measured nutritions in the water coloumn: 24ppm Ca, 8ppm Mg, 25ppm Nitrate, 12ppm potassium, 1ppm Po4.
(Increasing NPK didnt fix anything. Last week, I also boosted the GH and dosed additional calcium + Mg, but doing so also hasnt fix anything).

So I can meanwhile rule out:
Ca, mg, Nitrate, potassium, Po4, Co2

The problem has for sure something to do with my micro fert mix and the traces ratio,
The traces mix adds daily (I increased last week B, zn, Cu and the Ludwigias response was good - but the other plants have not responsed well):
0,06ppm Fe (1:1:1 Fe-EDTA, Iron(III)citrate, Iron(II)Gluconate)
0,02ppm EDTA-Mn
0,004ppm Boron
0,0028ppm EDTA-cu
0,0024ppm EDTA-zn
0,0008ppm Mo
0,0002ppm Ni
0,00014ppm co
0,00012ppm li
0,00010ppm al
0,00010ppm va
What do you think is too high or too low in my fert mix and could cause such problems like shown in the pics?

I also have co, al, li,va in it, but I am no longer sure if those "so called benefical traces" are really benifical at last and if they could cause some issues, too.
What do you think?

60 Posts
Discussion Starter · #3 · (Edited)
Very good point with the iron and I have a general question about iron toxidity, too:
I dosed in past strong chelates like FE-HEEDTA, FE-DTPA, FE-EDDHA and was getting in the long run pale looking plants. My Boraras naevus were no longer swimming much around if there were 0,4ppm HEEDTA/DTPA/EDDHA iron in the water coloumn. The water was certainly somewhat discoloured (Fe-EDDHa pinkish the water).
My feelings in past were that you can not dose FE-EDDHA much higher than 0,02ppm daily, because small fish like Boraras seems to be sensitive if using EDDHA chelator. I was also not sure if high FE-DTPA levels around 0,3-0,4ppm could do some more harm in compare to high Iron(II)gluconate levels and decided weeks ago to drop using those strong chelates.
So my question is,
is there any difference in iron toxidity depending on used chelates?

My idea for the new traces mix was to build it in future around the fully biodigradable Fe-IDHA instead.
Unfortunatly Fe-IDHA is difficult to get and so I temporary switched to the current 1:1:1 solution based on Fe-EDTA, Iron(III)citrate, Iron(II)Gluconate.

And I guess, you are right that my current iron dosing may be too lean for such weak chelates.
I will increase iron to 0,12ppm like you recommend, but what about Manganese?
Should I also increase Mn to 0,04ppm? (to manage 1:1,5 - 1:2,5 Fe:Mn ratio)

How are you weighing out the micros by the way? Do you have a very accurate digital scale or are you diluting to reach the concentrations above?
I have a very accurate digital scale and dillute the ferts in destilled water.
So it is a liquid fertiliser. I reduced the ph with citric acid to Ph 4,5 - I think this should be ok, to keep the chelates stable - or?

60 Posts
Discussion Starter · #6 · (Edited)
The DTPA dosing was so that there were permanently ~0,4ppm iron in the water coloumn.
Doing so hasnt worked good and you overdose the plants with (DTPA) iron by doing so.
About EDDHA: Dosing more than 0,02ppm Fe-EDDHA did not do any direct harm to fish and i do not say it is any toxic -but- the fish change their natural behaviour under EDDHA dosing.
I personally guess, it still has something to do that even 0,02ppm Fe-EDDHA discolours the water.
I never tried dosing 0,1ppm FE-EDDHA daily, because it will tint yours water ugly redbrown and I can tell you the red colour did not go away.
You need to do some large water changes to get ridd off it.

Fe-EDDHa can imo still be used in very tiny amounts.
Even if you still add 0,005ppm daily - you will see (if you are not doing weekly water changes) a slightly water discolourisation.

All the chelated iron products should be bio-degradable.
Just curious: Are there any studies handy about the metabolic degradation of these agents in the water column over time?
Citrate and Gluconate are easy biodegradable
EDTA, EDDHA, DTPA, HEEDTA are known as bad biodegradable (compared to other chelates like IDHA, NTA, GLDA and so on)
Here you can see a 30days comparsion chart:

I also haven't really read any studies that say adding this form of iron helps plants grow better.
There was a German university study around Zinc-EDTA, Zinc-EDDHA, Zinc-DTPA and the study has shown that the zn uptake rate depends on the used chelator. The root grow was not the same depending on the used chelator. The zinc was also more or less toxic to the roots, depending on the chelator.
So if chelating agents make some differences on Zn uptake rate - why not on iron, too?

About Fe-IDHA, I still found this agriculture paper where the grow rate was compared to Fe-EDTA:
I personally never used Fe-IDHA under aquatic conditions - but since it is a biodegradable chelator, it is really worth a try.

Also one other thing. I noticed you are adding nickle to your micro nutrient mix.
I am also not sure about Ni,
the only informations I was able to gather was that it enables in some plants the Urease enzyme and should "perhaps" also be benefical in generel for nitrogen uptake, too. Well yesterday I noticed after dosing the old trace mix with all those benefical traces that few minutes later some plants were bending their leafs.
Today I mixed a new bottle with increased iron and temporary removed all benefical traces (ni, co, al, va, li) - just to be sure that nothing from this stuff makes perhaps some hidden trouble.

60 Posts
Discussion Starter · #8 · (Edited)
Yesterday I measured iron and it was 0,08ppm in the watercoloumn.
This is very strange, because my iron dosing was during the last weeks still low.
Neverhteless,yesterday I dosed the new mix and 0,12ppm like recommended.
I measured today again and there are now 0,1ppm iron in the watercolumn. Since citrate/gluconate break down quickly, it just shows the iron (from Fe-EDTA) still accumulates and that the plants dont take up (for some reasons) any iron.

I watched now some fast growing weed like the Heteranthera very close and noticed that the chlorosis did not start from the tip/end - it start from inside the leaf.
It seems something induced anyhting that reduces the iron uptake and I decided to dose 0,001ppm Zn more, but the Heteranthera showed still very little signs of recover. So I decided to dose also additional 0,05ppm Manganese and 4 hours later the leafs were looking much more green.
Plants like Limnophila Guinea Broad Leaf are known as very sensitive and that they can quickly melt or recover and the Limnophila also appreciated the extra Mn dosing.

My temporary conclusion:
It seems not to work just to increase only Iron.
Manganese seems also be involved, perhaps zn/cu, too
( I am not sure if a higher Cu level could perhaps have some antagonistic effects on iron/manganese uptake)

Well, this certainly opens the question - how to optimize now the other traces dosing rates.
Mn should be added more, the question by all this is still "how much for beeing successfull in the long run".

60 Posts
Discussion Starter · #13 ·
I altered the fertiliser yesterday again:
0,16ppm Fe
0,04ppm Mn
0,18ppm Mg
0,56ppm K
Those 0,16ppm Iron are now from: 0,04ppm Iron-IDHA ; 0,12ppm Iron(II)Gluconate

My Limnophila Genua was looking today a little bit pale, just only 20minutes after dosing it looks again green. The current chelate combination seem too work a lot faster then the old EDTA/Citrate/Gluconate mixture.
I also raised Mg, but I am unsure there and never tracked Mg uptake.
Do you think it is "ok" or did it add perhaps too much Mg in the long run?
(I do not perform weekly water changes)

Toxicity causes plants to slow down their growth rate, but you will also see interveinal and marginal chlorosis in older leaves.
Do you have any closer information about the ppm rate when Mn toxicity happens?
I researched the web, but still found this comment from a duckweed study:

"Wang (1986) conducted 4 day acute and 7 day sub-chronic tests on the effects of manganese on the growth of duckweed (Lemna minor). The study was conducted using tap water at a pH of 7.5 (no hardness or temperature data provided) and the exposure endpoint was growth as indicated by the number of fronds initially and at the end of the exposure period. Twenty colonies of duckweed were studied and an EC50 (reduction in frond growth in 50% of test organisms vs. controls) of 31 mg/L was derived."

Seems 31mg/L (?) is EC50 for duckweed?
Unfortunalty, about other plants i found nothing.

60 Posts
Discussion Starter · #14 · (Edited)
Some new pics how plants response.

Good news: Stargrass + Nesea (Ammania) Golden recovered and I can confirm it was iron deficiency there.
Sp. Golden is meanwhile getting a new strong sideshoot, looks good so far. :) In the second tank the sp. golden looks also a lot better.
Bad news: Rotala Vietnam shows few recover signs, but looks way too small and still poor Rotala overall grow rate.

It seems the problem with the dark green older leafs is also not fixed and Limnophila Genuia shows today some melting :rolleyes: old leafs.
(Nitrogen is 12-15ppm , phosphate 0,2-0,5ppm, potassium ~10ppm)

The plants show daily uptake from: iron, phosphate, potassium
but still use little nitrate. Seems they are somehow limited in their nitrogen uptake - any nutrition that can cause this?
What is with molybdenum , is it perhaps too lean - how much should be daily added?
( I browsed yours and also APC deficieny finder - I can see @APC few molebdenum deficiency thumbails:
But I cant open the images and get a blank "Php error message". How to get those images in fullsize ??)


60 Posts
Discussion Starter · #16 ·
Well, I meanwhile think that too much copper induces iron deficiency.
After reducing copper, some plants (primary Neseae, stargrass) were doing a lot better, but unfortunaly not Rotalas. Since I can now rule out copper, left is zn, mn, b (mo)
My focus moves first to zn and then, mn and b.

Based on this study I believe the appropriate copper levels are around 0.03 Cu for good long term growth. Anything over that and you should start to see general decrease in growth rate. For zinc 0.08 seems a safe baseline value to shoot for.
Have you ever tested those levels in planted tanks with sensitive plants?

60 Posts
Discussion Starter · #18 ·
I daily dosed up to 0,0056ppm and plants like Limnophilias, Ludwiga, Cryptocorgnye were doing ok. (other plants will not do that good)
High copper levels seem also to enhanced red colurs from Ludwigia Red
(attachment: left pic stock cu dosing -> right pic high cu dosing)
The Ludwigia seems also not to get any chlorosis even at high copper dosing, but you can see that some leafs are bending down. (imo a first sign off too high long term copper dose for Ludwigas)
Green plants instead seem to get chlorosis like seen on Heteranthera. Such copper induced iron chlorosis can be override for some percent by heavy iron dosing, but bottom line is that Copper sensitive plants simply dont like high Cu levels.

The other thing is the Cu/Zn ratio - if you add 1:3, 1:1, 3:1 or whatever so.
Doing so seems also too make a difference. The Heterantera seems to prefer more zn rich dosing like 1:2 or so. If you dose a 2:1 ratio the plant seem to get in trouble.


60 Posts
Discussion Starter · #19 ·
got all problems finaly fixed.:third:
The reason for the problems was the substrate, it released something that was toxic :eek: for the plants. So yes, it was a toxicity.

I replaced the substrate and still few days later nearly all plants were growing healthy. (still a few needed some days longer for recovering). I also improved the fertiliser mix a little bit and it works now fine.
The both images shown average 5 - 6days growth rate.

So if you also consider some strange growth problems in yours tank that you can´t track down, perhaps also take a look at yours substrate, too. It could be in some cases a trouble maker as well.

60 Posts
Discussion Starter · #21 ·
It was gravel from pet store that shouldnt release anything, but my tap water has 22ppm Calcium and the tank ended up at 60ppm :eek: Calcium with that substrate.
The substrate released chalc and other things in the big way and the tank got at last a very bad Ca:Mg ratio in conjunction with high KH/GH (hardness).
I replaced the bad substrate with ADA Africana and everything was quickly fixed.
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