# Too much Boron = stunted growth



## kekon (Aug 1, 2005)

I carried out an experiment with dosing additional Boron. I suspected Boron deficiency as my Rotala and other plants have stunted and deformed tips. At the beginning of the week i added 0.05 ppm of Boron as H3BO3. At the end of the week i did 50% WC as usual and started to dose micros from "strong" gardening fert. I was dosing 0.005 ppm Boron from the fert
during the next week. At the end of the next week the results began to show:

- chlorosis on young Difformis leaves;
- Umbrosum & Rotala Rotundifolia stopped to grow completely

I used fert which has Fe:B = 6.5 : 1 ratio (TMG has 17.5 : 1) I was dosing 0.03 Fe daily so the overall accumulation of B is teoretically 0.05 ppm (assuming no Boron is added after WC and plants don't uptake it from the water). 
The same issues as described above were noticed by a person i know. He used tap water and TMG. He also noticed stunted growth. The more TMG he was adding the more severe stunted growth occured. Finally he measured boron concentration in a lab:

- when plants grew "so so": B was 0.09 ppm
- when chlorosis and stunted growth occured: B was 0.15 ppm

The culprit was high boron concentration in his tap water. He made his own fert eventually but without boron (the rest in the fert was exactly the same as in TMG; i mean, all the micros ratios were the same as in TMG). He began to dose his fert and plants started to grow healthy; no chlorosis, no stunted tips.


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## fabry (May 13, 2005)

Hi Kekon,
Please take a look at the following link
www.hhdwa.iinet.net.au/TL413.pdf

The ratios between the micros listed there are more or less the ones used 
in all the hydroponic cultivation farms.
The ones for aquatic/aquarium plants are not different.

From this chart you will see that at the normal Iron concentrations kept in cultivation tanks (1 - 2 mg/l of Fe as FeDTPA) the concentration of Boron goes from 0,258 mg/l to 0,516 mg/l.

A concentration closer to 0,5 mg/l is needed for some species.

But again, that depends a lot on Calcium concentration.

So at Ca levels of 110 mg/l like in the chart of the link I posted you usually really need something like 0,2 - 0,3 mg/l Boron for most of the plants to thrive.

If you go lower with Ca you may need less Boron.

Please remember that there is a correlation between the two elements due to interaction/antagonism.
So a higher concentration of B is needed when Ca is higher (or you will see B deficiency symptoms) and a lower concentration of Boron is needed when Ca is lower (or you will see Ca deficiency symptoms).
The similarity in the deficiency symptoms of the two elements complicates the matter even further.

So when talking about Boron please refer also the corresponding Ca concentration in the tank.

P.s. Most likely Boron excess/toxicity (usually for concentrations higher of at least 1 mg/l) becomes evident mainly as a damage on the external part of older leaves.

Best regards.

Fabrizio.


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## kekon (Aug 1, 2005)

Well, the person who had 0.15 ppm of B had also 66 ppm Ca and 20 ppm Mg and he noticed the issues i wrote about. A friend of mine made his micro fert using the following ratios:

Fe: 100
Mn: 50
B: 30
Zn: 30
Cu: 10
Mo: 1

These ratios failed to work (arguably due to chelators quality). He dosed 0.01 ppm Fe daily from his fert. However, at the begining it seemed to work well but he noticed sudden growth deterioration eventually. I have about 25 ppm of Ca and 5 ppm Mg now but i will raise Ca to 32 and Mg to 8 (i noticed Mg deficiency when Mg was 3..4 ppm). In my case plants stopped to grow as well  I was wondering why TMG fert has Fe:B ratio 1:17.5... 
Another issue concerns making our own micros ferts. Although we have separate chelators (Fe, Zn, Cu, Mn, DTPA & EDTA) in powder form designed originally for gardening purposes but i'm not sure if they work well in planted tank conditions as they are not designed for such purposes. They are prepared to be dosed directly into the soil. When mixing the chaltors together in distilled water, bubbles are generated in the solution. It's probably due to chemical processes in the solution which in my opinion may destroy the chelators or make them significantly less efficient. I'm going to ask the company that produces the chelators some questions about mixing them in one solution. Anyway, i came to the conclusion that TMG fert is the best choice but with adding at least 200% of the recommended dose. Also, additional Fe (and Mn probably) would be a good thing (added during WCs)
So, taking things altogether i think i must work harder over Ca/Mg/K ratios...
otherwise i will never get out of troubles with deformed and stunted tips...
Nevertheless, your clues are very valuable and they heve changed my approach to planted tank hobby recently...


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## fabry (May 13, 2005)

Kekon,
the argument is so wide that is impossible to explain/discuss everything here.
I suggest you to do some research (also on the internet) about the nutritive solutions used in soilless/hydroponic cultures.
Take a special care about the micronutrients and their ratios (that are even, in a certain measure, species specific).
Even if you are a navigated aquarist and a very intelligent guy (as you really seem to be) it will be very interesting and you will learn a lot.

Coming back to our discussion;
The ratios depend also on the chelators used.
That is because they depend on how easy is for the plants to grab the metal from its chelator and this depends on how tight the chelator holds the metal.
Every metal has a different stability constant with a different chelator, so you can see that there are many combinations possible.

I would advice you to work with FeDTPA, MnEDTA, ZnEDTA,CuEDTA, boric acid and sodium Molybdate.

It can be interesting also to work in the beginning with metal salts without amminopolycarboxilic acids (EDTA,DTPA,EDDHA etc.) as chelators and go with 'almost' non chelated salts.
This should allow you to see faster results with your plants when you are still experimenting (for example with new plant species). 
You can use, for example, citrates or ascorbates.

But consider that when working with poorly chelated salts (even EDTA can be a poor chelator for Iron in some circumstances) plants often go in deficiency of Boron and Molybdenum.
That is because Iron (and not only) going out from the complex and precipitating as Hydroxide will cause some anions (like phosphates, borates, and molybdates) to co-precipitate with it thus depriving water column.

Consider that for the synthetic chelators above to work it is advisable to have a minimum concentration (let' say above 0,2 mg/l Fe) for the plants to be able to uptake them with a speed capable to sustain a good/rapid growth.

About TMG, looking at its composition what I can tell you is that you are right.
You will have to dose probably 200% to 400% the recommended dose for a good growth (depending on the other parameters).

For what regards Ca/Mg/K I would advice you to go for something like:
Ca: 40 - 60 mg/l
Mg: 10 -20 mg/l
K: somewere in between the two (let' say 20 - 30)

If you add No3 solely as KNO3 you will have more than enough K and you do not have to worry about it any longer.

I usually keep No3 at about 10-20 mg/l and PO4 at about 1-2 mg/l.

Do not go too high with Sulphates and Cloride (I know you are already doing it) as this can influence the uptake of other anions like Borate and Molybdate.

In this way you can 100 % forget about Ca, Mg, K, N, P and their ratios and concentrate on the others (namely the micros).

When you do your experiment please consider that lots of interactions are possible, so is impossible to say what is going on just reading something like: I kept X at Y mg/l and I noticed this...
It is fundamental also to know *all* the other parameters.

I am interested in what you are doing so, if you think I could be helpful, I would like to read more details about your experiments (and see some pictures of the plants with the problems when they present).
You can contact me also via private mail (if you want of course).

Best regards.

Fabrizio.


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## kekon (Aug 1, 2005)

All my problems began when i switched from commercial NPK fert (N was in urea form) to KNO3 and KH2PO4. There is a planted tank company in Poland that produces a few fertilizer kits. One of them is prepared for "advanced users". It consists 4 500 ml bottles:

1. "Hydro Mineral" - for reconstituting RO (it's similar to Barr's GH Booster and Equilibrium (of Seachem)
Using recommended doses Ca = 13, Mg = 4, KH = 2
2. "Micro" - for dosing only to changed water (micros ratios are unknown unfortunately, but it consists also Titanium, Silicon and Cobalt)
3. "Macro" - NPK fert (N in urea form) can be dosed to changed water or daily if the tank is heavily 
planted.
4. "F" - for daily dosing. It consists micros of ratios which you have probably read in one of my post:

Fe: 2100 ppm/L (DPTA)
Mn: 1000 ppm/L
B: 150 ppm/L
Zn: 150 ppm/L
Cu: 80 ppm/L
Mo: 1 ppm/L

Recommended dosage: 2ml/30L - it gives 1 ppm Fe per week. 
I used that ferts kit with very good results. I didn't have any deficiencies despite low Ca and Mg (13 and 4 ppm respectively). But i had some issues with thread algae and BBA. Some day i was told "Macro" fert consisted urea which is the main cause of algae. I stopped to use "Macro" fert and switched to KNO3 and KH2PO4. I wanted to have 1 ppm PO4 and 10 ppm NO3. When i reached those levels plants stopped to grow. I got severely twisted and curled leaves and stunted tips. K was 27 ppm. Of course, it was low Ca - only 13 ppm. I doubled Ca and Mg then. Plants responded with healthy growth but only when K was low - below 10 ppm. Each time K was higher i got twisting, curling and slower growth again. Then i was told it was too little micros so i increased micro dosage. Things went even worse after that. The plant growth was slowered even further. "F" and "Micro" ferts consist high B concentrations so i thought it was too much B. The typical Ca and Mg in my tank vary from 25..30 for Ca and 4..6 for Mg. I suppose they are too low. I tried to keep higher Ca but it was only 2..3 weeks so it was not enough time to see any improvements in case of Ca & Mg deficiency. That's why i finally went to do something with micros ratios. At first i bought fert just for hydroponics:

Fe: 1.3% HEEDTA
Mn: 0.47% HEEDTA
B: 0.2% 
Zn: 0.1% HEEDTA
Cu: 0.1% HHEDTA
Mo: 0.03%

for more details you can open this link:

http://www.intermag.pl/en/produkty/nawozy_ogrodnicze/mikro.html

I was using this fert for a week (0.03ppm Fe daily) but it failed as well. My umbrosum stopped to grow completely (so did Rotalas). I attributed it to B excess.

The next step was buying separate chelators:

Fe: EDTA, DTPA, 8% Fe
Mn: EDTA (AM 4), DTPA, 14% Fe
Cu: EDTA, DTPA, 12% Cu
Zn: DTPA 14% Zn

So far i didn't make my own micro fert using them because i'm not sure if the chelators are good for planted tank.

My friend made his fert using chelators of ratios:

Fe: 100 (DTPA)
Mn: 50 (IDHA)
B: 30 (H3BO3)
Zn: 30 (IDHA)
Cu: 6 (IDHA)
Mo: 1

He dosed 0.01 ppm Fe daily from this fert but it failed - growth was stunted eventually.

So, the next step i have to make is to raise Ca & Mg as you have said. To reconstitute RO i no longer use CaCl2 as i get withered leaves on my Alternatera any time Cl is over 10 ppm. I use CaSO4 and MgSO4. It also raises SO4 to 70 ppm (is it too high ? I don't know what SO4 levels may be harmful). Doing this way I have 7.5 ppm Mg and 16 ppm Ca. The rest of Ca - 16 ppm comes from CaCO3 (put in my RO filter in additional chamber; it's CaCO3 in a gravel form 2..5 mm seeds). Finally I have 32 ppm Ca and 7.5 ppm Mg. I can also dose additional amonuts of CaCO3 into my canister filter but it usually takes a few days to dissolve.
Maybe i should also use the chelators i bought ?
Unfortunatelly we don't know IDHA and DPTA chelators quality...

Here you can see how my plants look like (maybe you've seen them before):

http://www.aquaticplantcentral.com/...26555-can-ca-no3-3-be-harmful.html#post194668


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## Zapins (Jul 28, 2004)

How did I not see this GEM of a thread before? Its taken me 3 years to find it - Aghh!!!

I'd like to see some updates on this. Have your problems subsided kekon?

Also, the links don't work anymore. I'd love to look at them. Do you have the info somewhere else?


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## kekon (Aug 1, 2005)

> Have your problems subsided kekon?


Well, i'm still testing on this. However i'm really confused as to why some people add fertilizers containing so much boron with excellent results and why it doesn't often work well in my tank...
Once i noticed boron deficiency on Macrandra and adding boron helped a lot for this plant (i wrote about it in the "How to make rotala macrandra grow" thread). But some other plants didn't tolerate higher boron doses. From what i know when high boron is present also zinc level must be elevated in many cases to prevent "sensitive-boron" plants from stunting. Usually most fertilizers for terrestal plants contain 2x more boron than zinc (so do many planted-tank ones as well). There is one thing however that is difficult - i don't have any possibility to measure level of boron in the water in my tank. There is a laboratory in my town which examines soils and water samples for many nutrients. Unfortunately they don't measure boron levels so i don't really know how much boron there is in my planted tank. I made two different fertilizers: one of them added 0.02 ppm of Zn and 0.01 ppm of B weekly. I used this fertilizer for several weeks. Then i made another fert which added 0.02 ppm B and 0.01 ppm of Zinc. Also, i tested it for several weeks. I didn't draw any clear conclusions from the experiment... Once i was told the RO filter removed only 50% of boron from the tap water. The tap water in my region usually contains much boron - usually 0.05-0.1 ppm. I think such high boron content might have disrupted my experiements


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## Jdinh04 (Oct 7, 2004)

Subscribed


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## Diana K (Dec 20, 2007)

"I think such high boron content might have disrupted my experiments "

When doing tests like this either use RO/DI water, or completely test the tap water and count it in as part of the supply of nutrients. 

Boron is also toxic to land plants. Some plants can tolerate more than others, but I have had landscape clients unable to use their well for irrigation due to high boron. One well measured 4 parts per million if I remember. (It has been quite a few years)


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## Elkmor (Mar 30, 2005)

kekon, try AquaSoil. It solves most of problems with RO water, with "toxicity of boron" (in my case) too.


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