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...

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.

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

Revan

Very interesting experiment

Thank you for sharing the results

Best Regard

Glouglou

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

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

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

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/f...w-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

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.

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

kekon

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.