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Tropica have adopted the Duckweed Index

dw1305

dw1305

Expert
UKAPS Team
Joined
7 Apr 2008
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nr Bath
Hi all,
All right, so the title might be <"slight hyperbole">, but the <"Tropica "Amazon Frogbit" (Limnobium laevigatum) page"> says:
Limnobium laevigatum from South America is a decorative floating plant that is particularly suitable for open aquariums. 1-5 cm tall and leaves from 5-15 cm wide.

It is also good in traditional aquariums, because the fine, long and decorative roots provide protection to gouramies and other surface fish that like the roots of floating plants. If there are enough nutrients in the water and the light intensity is good, new leaves will appear above the water surface. It may become necessary to remove some to avoid that the plants beneath it still gets some light.

When the nutrient level in the water decreases, it will grow much slower which makes it a great indicator of the available nutrients.
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cheers Darrel
 
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dw1305 said:
Hi all,
All right, so the title might be <"slight hyperbole">, but the <"Tropica "Amazon Frogbit" (Limnobium laevigatum) page"> says:

cheers Darrel
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That is very nice Darrel. I am a big fan of the Duckweed index as you know.

"When the nutrient level in the water decreases, it will grow much slower which makes it a great indicator of the available nutrients."

In my experience (and opinion), the Duckweed index is not really about speed of growth, but rather serves as an indicator of nutrient balance (do I dare say ratios... ) or lack of it and lack of specific nutrients. I run two low-tech tanks. One is dosed very lean the other slightly more. In the tank where I dose very lean the individual plants tends to grow much larger with much less propagation. In the other tank where I dose higher the individual plants remain relatively small, but the propagation rate is very much higher. In both tanks the frogbit looks very healthy. In terms of frogbit plant-mass I think its a wash between the two tanks. So apparently, nutrient demands are met in both tanks, but growing pattern and propagation rate differs.

Cheers,
Michael
 
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Hi all,
Witcher said:
hopefully they won't claim an ownership of this idea like many companies do
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I don't think <"I could patent it">.
MichaelJ said:
In my experience (and opinion), the Duckweed index is not really about speed of growth, but rather serves as an indicator of nutrient balance (do I dare say ratios... ) or lack of it and lack of specific nutrients.
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I honestly <"think it does both">, but I'm obviously not an <"objective viewer">.
MichaelJ said:
In both tanks the frogbit looks very healthy.
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Agreed, that is usually what interests me, much more than growth rate.

If people use the Duckweed Index I'm pleased, it doesn't make me any wealthier, but it definitely <"makes me happier"> and I think it gives the non-expert planted tank keeper a mechanism that simplifies planted tank keeping.

This is from <"Apistogramma forums">.
...... Which I am actually following now days........ Then you can be even prouder, I have at least a dozen of people that in turn got it from me here in Germany. None of them has had any problems with their plants since.
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cheers Darrel
 
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dw1305 said:
I don't think <"I could patent it">.
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To my knowledge, this falls into the category of a novel observation, discovery or theory , which generally can't be patented. Also there would need to be a physical (tangible) embodiment - say if you originally would have developed the Leaf Color Chart to accompany the Duckweed index to identify nutrient deficiencies then it likely could have been patentable and trademarked. Luckily for us here on UKAPS that didn't happen as you would be way too busy counting money 🙂

Cheers,
Michael
 
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Hi all,
The grumpy one said:
I will start it off and others can add text.
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I like that, but it looks much too professional for me.

Hypothetically all I would need to do is re-run this <"The scientific background to the "Leaf Colour Chart""> experiment, but with randomised single rosettes of Limnobium laevigatum and a lower range of nitrogen values.

I then just match the colour and NO3- level for my <"standard nutrient solution">, get wet mass / dry mass, leaf number etc. I could use calcium nitrate (Ca(NO3).4H2O) as my nitrogen source and either ignore the differing calcium content? or balance that with calcium chloride (CaCl2.nH2O).

Urea (CO(NH2)2) or ammonium nitrate (NH4NO3) would be other "nitrogen only" options. I could also use sodium chloride (NaCl) to achieve a standard conductivity value etc.

Rather than a bespoke mix I might start with <"Tropica Premium"> (before anybody asks "cloned", rather than purchased) as my "vanilla" base fertiliser (I knew there must be a use for it), but I'd still need to add some phosphate (PO4---), but because that level will be the same in all the treatments I could use any soluble phosphate salt.

An even easier option would be to start with a very low dose of a standard fertiliser (let's say <"Solufeed 2 : 1 : 4">) and then increase the concentration, but you couldn't then isolate the effect of increasing fixed nitrogen values.

cheers Darrel
 
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dw1305 said:
Hi all,

I still haven't written a proper "Duckweed Index" post, but this might be the catalyst.

cheers Darrel
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Hi Darrel, It would be great to have a good sticky post from you that we can refer to when discussing nutrient deficiencies and recommending the Duckweed Index. I suppose you could compile a good writeup from your numerous posts on the topic.

Cheers,
Michael
 
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