Is it possible that too much Fe, Ca, Mg or other trace element poison plant?

[Shad0w]

Is it possible that too much Fe, Ca, Mg or other trace element poison plant? In other word too much micro nutrient will poison/kill plant?

My understanding until now is plant only take just what its need from the water/soil. I mean if plant require only 0.1ppm (just arbitrary number) of iron a day then it will take only 0.1ppm even though there are more than 1ppm of iron in the water/soil.

If it is true, than Fe, Ca or Mg poisoning in plant will not be possible.
I'm reading in other forum, people was suggesting about Fe or Ca poisoning. I hope somebody can enlighten me on this. Thank you.

 

[jonny_ftm]

Of course, extreme conditions with very high concentrations of some nutrients can be toxic for living organisms, plants as like as animals.
However, for iron, Tom showed that very high concentrations are safe even for living stock (>10ppm?)
For calcium, extreme hard water (very high GH and KH) can be hostile to some plants.

So nothing new, but, if you follow the advices here (EI/low tech...) you won't see any poisoning. Most people claiming nutrients poisonning never looked for other causes to their plants decaying or algae blooms.

 

[Shad0w]

The issue is sound more like indirect effect. It is not because plant taking to much but more like due to high concentration the evirontment no longer suitable for plant to grow. Is that correct?

and only happen in extreemly high, Fe > 10ppm, how about other trace? unless I miss some part when reading EI, I don't recall it mention about ppm of other trace mineral.

 

[Tom Barr]

In natural systems where no new nutrient is being added, or where the soil is toasted and poor anyway, things may occur, but this is very rare in aquatic systems in nature.
I think some of the concern is more based around fear and agriculture extension advice for crops.

Then aquarist apply that directly without any caveats to aquarium plants.
That is a dangerous assumption.

Copper is a trace and is used as a way to kill snails, inverts etc, shrimp etc.........but it is also a nutrient that essential, copper is also used as an algicides and a herbicide at higher concentrations.
It is rare than anyone will add so much using something like CMS or other brands of Traces.

You'd have to make a couple of orders of magnitude dosing mistakes to get there.
If that is the case, you should not be keeping aquariums to begin with due to a lack of competency.

I've dosed very rich for Traces for a long time.
At higher levels, I really do not get much positive effect or negative effect.
So I settle on a lower dosing, say in the 0.5 ppm range per dose 3x a week or so.


Regards,
Tom Barr

 

[Tom Barr]

Optimal growth rates for Fe was found to be 6ppm for Hydrilla FYI. One of the few studies on aquatic plants and chelated Fe.

As far as Ca, most plants are fine over a very wide range, same for Mg.
KH is quite another matter and needs separated from GH.

Regards,
Tom Barr

 

[Shad0w]

Optimal growth rates for Fe was found to be 6ppm for Hydrilla FYI. One of the few studies on aquatic plants and chelated Fe.

6ppm? That is very high I though recomended concentration for Fe is only 0.2-0.5ppm

 

[dannyfish]

6ppm? That is very high I though recomended concentration for Fe is only 0.2-0.5ppm

Hi Tom

need your advise...

my tank 55litres (15Gallons)
can i also dose 6ppm as you mentioned?..

 

[dannyfish]

Optimal growth rates for Fe was found to be 6ppm for Hydrilla FYI. One of the few studies on aquatic plants and chelated Fe.

As far as Ca, most plants are fine over a very wide range, same for Mg.
KH is quite another matter and needs separated from GH.

Regards,




Tom Barr

Hi Tom

need your advise...my tank 55litres (15Gallons)
can i also dose 6ppm as you mentioned?..

 

[Tom Barr]

Well, I'd not really recommend it
Stick with 10X less or maybe even less.

The question is whether you are really limiting the nutrients, and having negative impacts from adding not enough, adding more is wasteful, and a little is okay, just not a lot.
We ALL WASTE some nutrients and some light and a lot of CO2 typically. The goal is to reduce it where it does not affect growth much and cost us less, and also dose the amounts/frequencies that best suit us and our own habits.

Regards,
Tom Barr