# Ca, Mg, K, NO3, PO4 - mysterious summary



## kekon

After a year of experimenting i decided to put my observations in order. This especially concerns stunted tips issues often met in many tanks:

lighting: 4 x 30 W (3000K)
1 x 30W (6500K)
2 x 8W (2700K)
T = 24C, plain gravel witout any additions, lighting turned on for 12 hours, CO2 dosage switched off at night, aeration switched on at night, external Eheim 2213 filter.

water params: plants health:

Ca = 10, Mg = 4, PO4 = 0.1, NO3 = 2, K = 15, CO2 = 10 very fast growth,
no stunting at all,
heavy micro 
 dosage, high iron 
demand, no NO3 
dosing at all 

Ca = 10, Mg = 4, PO4 = 1, NO3 = 20, K = 27, CO2 = 10 i'd say... savage butchery; many
plants stunted,
deformed, twisted
leaves, growth
stopped, some red
plants die

Ca = 25, Mg = 5, PO4 = 1, NO3 = 10, K = 10, CO2 = 20 slight improvement
but some plants
still severely 
stunted 

Ca = 25, Mg = 5, PO4 = 1, NO3 = 10, K < 3, CO2 = 20 improvement, 
stunted tips go 
away but K 
deficiency 
appears

Ca = 19, Mg = 8, PO4 = 0.2, NO3 = 2, K = 10, CO2 = 20 considerable
improvement, no 
stunted tips

Ca = 35, Mg = 8, PO4 = 0.2, NO3 = 5, K = 15, CO2 = 20 some more 
stunted tips 
appear

Ca = 35, Mg = 12, PO4 = 0.2, NO3 = 5, K = 15, CO2 = 10 very slight 
improvement but
some new 
Polysperma leaves
curl upward along
edges after 3 
days of adding Mg



So... my next step is to restore contidions i had a year ago... which means very soft water...


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## Ajax

Very interesting post. I know the first thing some members are going to ask is how can you verify the readings you got. That is actually almost irrelevant though if you used the same method/equipment to test each time. If you compare the readings you got against the conditions of the plants, the actual nutrient levels are not all that important. 

This just validates what Amano has been doing for years....softer water & minimal fertilizing is the way to go.


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## kekon

I forgot to add which plants were affected or not affected:

plants with stunted tips: umbrosum, alternathera reineckii, 
hygrophila corymbosa
plants that grew very well at high NPK: Blyxa japonica, H.callitrihoides,
aromatica, cabomba caroliniana,
hygrophila zosterifolia
plants that didn't react much: didiplis diandra, bacopa caroliniana,
polysperma rosanervig, glossostigma
elatinoides, anubias barteri var. 
nana, hygrophila difformis
plnats that were "lazy" to any changes: rotala rotundifolia


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## Revan

Very interesting experiment

Thank you for sharing the results

Best Regard


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## Glouglou

*Hum!*

This is very interesting.
The number Kekon give are really close to the PMDD of Sears & Collins.



> heavy micro dosage


Ok, fast growing, healty plants, lots of Iron & micro.

Kekon
- at what concentration you keep the iron (mg/l)?
- do you consider the tank to be heavy, moderate or lightly planted
- the size of your tank was?

Cool:tea:


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## kekon

When it comes to iron, when i had great growth and very soft water, i kept about 0.3 ppm Fe (Sera Fe test kit). Obviously we can't rely upon test kits.
My tank volume is 200 liters. The tank has always been heavily planted and it has always been dutch style tank.
I did 25% water changes each week. It was only RO water reconstitued with commercial mixture that was composed of CaCO3, MgSO4, KHCO3, and probably very little amount of CaCl2 (as a source of Cl) and very little K. However, i also used commercial NPK fert which had plenty of K, some PO4 and very little NH4 (the daily dose added about 1.5 ppm K, 0.1 ppm PO4 and 0.0025 ppm NH4)

I used a fertilizer which was:

Fe: 0,21%
Mn: 0,1%
B: 0,015%
Zn: 0,015%
Cu: 0,008%
Mo: 0,0001%

I dosed 4.5 ml daily. I had about 20 fish in the tank and i think that it was enough nitrogen produced by fish because NO3 stayed 2 ppm all the time without any additions from KNO3, Ca(NO3)2 and plants grew like crazy. I had to prune plants every week so it became very tiring  
When i switched to TMG and set NO3 to 10 ppm, PO4 to 1 ppm and K to 10 ppm all the plants began to grow very slowly. Even increasing Ca to 50 ppm didn't help - it seemed to be even worse


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## Freemann

Very interesting Kekon. This is the kind of postings that I am interested more than anything. My basic problem is the quality of your test results. Let me tell you what, I am prepared to make all the tests for you in my colorimer for NO3, PO4, Fe3-Fe2, and the turbidometer for K all I need is 60-70 ml of water from each different stage of your experiments we live next to each other so mailing a batch of water samples won't be a problem, this way you can have verified results, I doubt you do have this now with all the useless tests in the market and it is a pity not to be able to have the results you should.
Ok now for my own observations, I can confirm aswell that to much NO3 (like adding 30 ppm weekly with one or even two 50%water changes) cause severe deficiencies here as well (hygrophilas, ferns, ludwigias, rotalla indica, umbrosum plus a number of others, were the most affected), PO4 does not seem to cause deficiencies here. Iron as you rightly say seems to be a catalytic factor in plant growth. Notice in Cavan's post here:
http://www.aquaticplantcentral.com/forumapc/science-of-fertilizing/33560-how-i-do-it.html
He adds 1 ppm Fe daily from both TE, Fe, while he adds only 1.3 ppm NO3 daily. Does that ring a bell?
Here adding Fe in huge amounts (1ppm daily gives a reading of 0.12 ppm on the water column) has been followed by explosive healthy growth in difficult plants including 2 Stellata variants, aromatica, ferns e.t.c species which I generally consider difficult, I keep PO4 guite high (2-4 ppm), and I don't add Mg anymore which I consider as well a probable cause for tip, plant stunting. Strangely enough adding even 1.5 ppm NO3 daily will give a reading of 28 ppm (sometimes even more) NO3, (I reckon fish pooh, organic matter through biological filtration contribute to that, this proves to me that the consumption of NO3 is much less than we think, still addition of K from KH2SO4 can bottom out NO3 in a day and in the process "burn" the plants. By the way tank is 408 gal, lights are 3x150w MH, 20 cm above the tank, 4.200 K, on for 6 hours a day. Tank is heavily planted currently. Algae conditions: tank is basically algae free with very few algae eaters, green algae appears in glass and grows pretty fast after 4 days from cleaning, very thin bga film appears in some very small bare areas of the fluorite and is removed together with detritus once a week (I do 50% WC split in 2 different days), plants that still stunting (growing but not proper is a better description) are HC, Some yellowing on few new but not all new leaves of anubias, nasaea sometimes stunts the tops sometimes not.
Gh 12, Kh 8, CO2>30 ppm all the time.
So I have to say that in some way I have come to the same conclusions, only thing is that my lights are on only for 6 hours and that maybe a factor on my healthier growth, improvement. Still I am pretty sure much more emphasis should be placed from all of us into the toxicity, interaction of specific ferts and the effect of this to our plant health.
Freemann


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## kekon

Thanks for reply and confirming my observations... I'm really impressed of amounts of iron he adds. I've never dosed such high amounts. The highest dose i've ever added into my tank was 0,05 ppm daily. It seems also chelator type plays important role. EDTA chelator is less stable and needs to be added in higher amounts. It also proved to contribute to algae growth.
HEEDTA and DTPA are used in TMG and are better quality. 
I think i should try with more iron now. I have very easy access to lots of different chemicals, salts, chelates. I have many of them at home and my workshop looks like chemical factory... I tried with NH4 in place of NO3 but it also casued many plants to stunt exactly like NO3 did. Last time i killed more than 10 fish by dosing NH4OH (ammonium hydroxide)... It was only 0.05 ppm NH4 daily but it turned out to be lethal... I ignored the fact that NH4OH is extremely toxic to fish (much more than other ammonium salts). The maximum allowable NH4OH concentration in the water column is 0.025 ppm. However, ammonium hydroxide is the best N fertilizer for plants but due to its high toxicity we must forget about it. 

I came to the conlusion that any form of N could stunt our plants. But i can't understand how some people (provided they're telling the truth) are able to grow such plants like Umbrosum for in soft water and high NO3 - in my case it just doesn't work ! Any attempt to raise NO3 above 5 ppm end with stunting. I know for sure, that high NO3 works well in hard and very hard water (say GH over 15)

As far as measuring water parameters is concerned i can tell that most of them were measured in a certified laboratory. The laboratory mainly tests soil and water samples for agriculture purposes. Also my NO3 test kit was verified there so i can assure my results are quite accurate. GH test kit readings were verified against Ca & Mg measurements in the laboratory as well. Potassium was measured in the laboratory many, many times. Basing on the results i estimated K weekly absorption by plants which tured out to be quite low - about 3 ppm per week. 
The measurements weren't expensive so i did them many times. They also measure micronutrients concentrations (except molibdenium and boron) but i never asked them to do it.


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## Revan

Cavan use Seachem Iron which contains iron gluconate. 
Gluconate is a weak chelator so I think that he doses extremely high iron amounts because most of the added iron precipitate and only a little part of that iron is uptake by plants.
If we use a stronger chelator like DTPA I think that we need to dose fewer amounts of iron.

I'm sorry for my bad English.

Best Regards


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## kekon

Revan said:


> Cavan use Seachem Iron which contains iron gluconate.
> Gluconate is a weak chelator so I think that he doses extremely high iron amounts because most of the added iron precipitate and only a little part of that iron is uptake by plants.
> If we use a stronger chelator like DTPA I think that we need to dose fewer amounts of iron.


Yes, you're right. I think the same. Some say weak chelators are absorbed by plants more easily but they stay in the water for not too long; i was told they were stable only for 8 hours while DTPA can be active for several days.
It seems Seachem also uses non chelated Cu, Zn and Mn; it uses CuSO4, ZnSO4 instead, but i'm not sure.


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## Salt

If iron precipitates, won't dosing high amounts of it eventually lead to the substrate becoming toxic?


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## kekon

I don't think so. If it precipitates it becomes insoluble and becomes unavailable to plants. Each time i clean my external canister filter i find lots of brown sediments there which is basically oxidized iron from the ferts i use.


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## Freemann

> I think I should try with more iron now. I have very easy access to lots of different chemicals, salts, chelates. I have many of them at home and my workshop looks like chemical factory...


You do that you will be surprised on the effects. Read also this I have written long ago.
http://www.aquaticplantcentral.com/forumapc/science-of-fertilizing/9608-the-fe-disappearing-act.html
look at my post on the second page
Also look at this post to Greg Watson
http://www.aquaticplantcentral.com/forumapc/greg-watson/6840-how-much-iron-do-you-dose.html
and some of my torments and questions in the past on the same tank:
http://www.aquaticplantcentral.com/forumapc/science-of-fertilizing/4789-iron-versus-high-light.html
Also notice this, it seems other people are noticing similar things:
http://www.aquaticplantcentral.com/forumapc/showpost.php?p=255633&postcount=11


> I came to the conclusion that any form of N could stunt our plants. But i can't understand how some people (provided they're telling the truth) are able to grow such plants like Umbrosum for in soft water and high NO3 - in my case it just doesn't work ! Any attempt to raise NO3 above 5 ppm end with stunting. I know for sure, that high NO3 works well in hard and very hard water (say GH over 15)


Well I wonder exactly the same thing. As I said my water with 12 Gh can tolerate 30 ppm NO3 (still even now with just the lower amounts hemianthus family plants don't grow, umbrosum barely does it, HC is so and so, micranthemoides just melts away), but dosing amounts of up to 30 ppm weekly positively causes huge problems allover even with 12 Gh.



> Some say weak chelators are absorbed by plants more easily but they stay in the water for not too long; I was told they were stable only for 8 hours while DTPA can be active for several days.


At the moment I am using Microplex for TE and iron gluconate in powder form as an iron source only, I have powder iron DTPA around as well and has dosed that in the past, my problem with strong chelators is the fact that even after the release of the iron or other metal bonded to it a chelator stays active in solution and bonds again metals, there was an article on some French plant book (don't remember the title) about chelators being absorbed by the plants and binding metals in the sap causing problems, I don't know what effects could this have in high dosing of chelated metals, gluconate on the other side being sugar like won't have this kind of effects.

I am on the same boat with you on this one kekon and up to now I have seen the best tank by reducing NO3 and increasing Fe, TE. I believe that here we have 2 different problems that coexist stunted growth is caused by high NO3 but at the same time low NO3 in combination with *high iron* eliminate stunted tips as well.
I am really happy with the results, tank looks at it's best for the last 5 months and getting better all the time. It also explains why my previous tank was doing so well for 4 years (I always dosed only 1.5 ppm daily NO3 there, I always use dosing pumps in all tanks)
I just wonder how the hell this has not come up earlier.



> As far as measuring water parameters are concerned I can tell that most of them were measured in a certified laboratory. The laboratory mainly tests soil and water samples for agriculture purposes. Also my NO3 test kit was verified there so I can assure my results are quite accurate. GH test kit readings were verified against Ca & Mg measurements in the laboratory as well. Potassium was measured in the laboratory many, many times. Based on the results I estimated K weekly absorption by plants which turned out to be quite low - about 3 ppm per week.
> The measurements weren't expensive so i did them many times. They also measure micronutrients concentrations (except molybdenum and boron) but i never asked them to do it.


I am happy you made sure you verified your results so well; this makes things even more valid.
I am pretty sure this is the breakthrough I have been looking for long time
Freemann 

PS


> If iron precipitates, won't dosing high amounts of it eventually lead to the substrate becoming toxic?


Think of it differently does a ton of laterite in the substrate is toxic?
I should worry more about TE, specially copper in commercial products like microplex is quite high.


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## Wheeler

Jeff Ludwig and I found very similar results a few years ago. Bad growth and LOTS of algaes with NO3 additions in moderately soft water. I had Fe, TE additions pushed to ridiculous amounts with no ill effect and great growth for a while, but I ran into some kind of toxic wall. I scaled TE way back and kept Fe the same and it was remedied shortly. It's been a while so I don't remember my exact numbers :|

Thanks for posting your thoughts. I'm in total agreement.


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## kekon

Freemann, the posts you gave links to, are very interesting. I read them thorougly. I see we all have very similar opinions. 
There is one problem though. Dosing much less NO3 and more iron helps many plants that were stunted but some of them really need high NO3 (such as Blyxa). They grow slowly in low NO3. I though of putting fertilizer sticks containing nitrogen under the roots while keeping low NO3 in the water column.


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## Freemann

> There is one problem though. Dosing much less NO3 and more iron helps many plants that were stunted but some of them really need high NO3 (such as Blyxa). They grow slowly in low NO3. I though of putting fertilizer sticks containing nitrogen under the roots while keeping low NO3 in the water column.


Well I tell you what; you could increase a bit you Gh. Here as I said 12 Gh at the moment with a 30 ppm NO3 reading on the colorimeter and dosing 1.5 ppm NO3 daily grows most of the stuff. As I said the hemianthus family is still struggling but plants like Stellatas that are supposed to need lots of NO3 are doing better than ever (in much higher NO3 concentrations they had stunting problems). I think as you said providing more in the substrate by various means could be the answer for these plants.
I would really be interested if other people like Wheeler with lots of experience would come forward and verify these observations.
Freemann


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## Laith

Interesting. I've always found that with harder water more ferts were needed. I have tanks with both hard water (GH 18, KH 15) and softer water (GH 6, KH 4) and I find that the harder water tanks will show deficiencies before the softer water tanks with the same mg/l dosing.

I have no idea what the cause of this is... I've always thought that perhaps the high carbonate levels interfere with plant uptake? and in the case of Fe and trace elements that the higher carbonate levels decreased the effectiveness of certain chelators (gluconate for example)...


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## kekon

I have an idea which worked very well for me in the past. I used 2 micro fertilizers (commercial ones). One of them is designed to fertilize only changed water. The second one was used daily and consisted mainly Fe and Mn. Dosing traces to changed water only and Fe and Mn daily (and it's best to do 50% water changes) ensures that water column in our tanks has stable and known micronurients levels. If you add "x ppm" of micronutrient to changed water it means, there will never be more than x ppm in the tank. 
As Freeman said, it would be good to dose higher Fe daily (i will also dose some Mn). We usually fertilize our tanks daily and do big water changes at the end of the week. But i noticed that large water changes (50%) cause plants to grow poorer at the beginning of the new week and they improve growth just before next water change. This is due to the fact that large WC dramatically decrease all nutrients level and many plants suffer from some deficiences. So it seems to me it's vero good do at least iron and manganese to changed water.
When i used the 2 separate ferts i didn't have such issues so i'm going to apply the idea again.


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## Revan

I think that your idea may be right, I thought something similar and I'm going to try something in this way.
Which brand of fertilizers did you choose?
Many Brands suggest 2 fertilizers that must be used one at the water change (to establish levels) and one daily (to keep more stable levels): for example JBL (ferropol + ferropol 24), Red Sea (flora gro + flora 24), Dupla (plant + plant 24) but none of these brands say the composition of the fertilizers.
I will try the JBL fertilizers, JBL doesn't say the exactly composition of these fertilizers but only that in the ferropol there are Fe, Mn, Zn, B, Co, Mo, Cu, K, S in a chealed form (I don't know which chelator is used in this product) and in the ferropol 24 there are Mn, Fe, Co, B, Zn, Br, Li, Ni, I, Sn, Ti

Best Regards


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## Revan

kekon said:


> It seems Seachem also uses non chelated Cu, Zn and Mn; it uses CuSO4, ZnSO4 instead, but i'm not sure.


The exactly composition of the Seachem's fertilizers is reported here:
Fertilizer Comparison
flourish
So it seems that you are right; Seachem uses ferrous gluconate and a not chelated form for the other elements (from sulphate)

Best Regards


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## kekon

When in comes to fertilizers i used 2 domestic products - one for changed water and one for daily using. I know the exact conntens of one of them. The fert for water changes contains additional elements such as Ti, Co and Si. I think i will use the Ferropol as you do.


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## fishyjoe24

bump, a old tread for a really good read. i always wonder what would happen if i dosed a little more of this and a little less of that.


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## tat

Very interesting topic.

I have one question.

On the first experiment,the changes were:
Before: Ca = 10, Mg = 4, *PO4 = 0.1*,* NO3 = 2*, *K = 15*, CO2 = 10
After : Ca = 10, Mg = 4, *PO4 = 1*, *NO3 = 20*, *K = 27*, CO2 = 10

Why plants reacted to so bad to the macro nutrients increment?


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