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Re: Allelopathic chemicals

"I'd like to know more about what there is about an established, in-balance 
tank that prevents significant algae. Is it simply a question of the 
thriving plants being able to out-compete algae for the sufficient, but not 
excessive, nutrients?  Or are the plants also putting out allelochemicals 
that actively keep algae in check? Do the gurus get the initial nutrient 
balance in a new tank just right and avoid those stages where you see every 
known type of algae? Or is part of the game necessarily waiting for a 
buildup of allelochemicals?"

No, the amount of interactions in most systems is very low to insignificant.
Basically, don't worry about it.
I have this talk with folks at the Aquatic Weed Center here and the Chairman
of the Dept etc.
We talked a few minutes, agreed on everything and went on our ways..........

I'd bark up another tree for plant tanks and algal applications.

"Now there's a product that would sell: a naturally occurring allelochemical 
that acts selectively on algae. I also wonder about the mechanism of 
allelochmical selectivity between plants. Species A inhibits species B and 
C but not D, E... What do such specific mechanism of action look like? We 
know the growing requirements of species can vary. Does this come into play 
in such mechanisms? Perhaps species A can get a certain nutrient via the 
roots and can produce a chemical that impedes leaf uptake, which species B 
depends on."

Each chemical needs to be carefully considered and each pair of interactions
of multiple sets etc.
Each and every plant may react completely different than another.

<< The Feasibility of Allelochemicals As a Means to Control Toxic 
Cyanobacterial (Blue-Green Algae) Blooms in Water Bodies[#2904]
Kinneret Limnological Laboratory (Israel)

BGA are not a great issue for planted tanks. A simple lights out for 3 days,  
 good cleaning and keeping up on things takes care of that.

Generalizing up to include all algae is as dangerous as assuming all plants
grow a certain way or affected the same by an allelopathic chemical.

Often times the chemical is ground up plant pulp and dumped into a tank with a
culture of algae.

Adding it naturally and slowly by the plant's own mechanisims can be difficult
to measure etc.
Isolating pure exact is doable but adding antiboitics would work also for

I think the main thing here is the cause for BGA in the first place,
eutrophication, most often human induced. Pollute the water, shift diatoms to
BGA in the water column.

That's the other issue here, the water column, this is not the Oscillitoria
that smothers a tank but Microcytis, which is phytoplankton. These are

"Will identify and characterize potent naturally occurring biochemical 
agents--allelochemicals--to control toxic populations of Microcystis in 
fresh water lakes. Will test the potential application of allelochemicals 
for bloom control under laboratory and small-scale field conditions. To be 
completed in 2004>>"

Yea, why not reduce human impacts instead? There are other much less expensive
methods. How much would be needed to add to say Lake Victoria in Africa? Who's
gonna pay for it? There are many other considerations that need asking when
applying this.
Adding a chemical such as copper sulfate has been used for years to kill
Folks need to reduce their impacts on FW water ways. Whether it's allelopathic
chemicals that cost alot or coppersulfate, it does not deal with the root
cause and the damn attitude that man should control all aspects of nature.
It's like having an out house spetic system next to your wellwater. I've seen
this here and other places. Amazing.

Water sheds need protected if folks care about them. Same goes for the sea,
it's big but it'll have the same problem sometime.

BGA goes through a cycle in many lakes every year but it's temporary, folks
want nature idealized and alway a certain way they think is best.

Our tanks have many other things that are faster, more effective and cheaper
to control this BGA or most other algae.

Shrimps are great, adding fresh mulm from another tank works super. Keeping up
on water changes, having a balanced fish load etc.

I think the main issue for newer tanks not yet stabilizied is the substrate is
not matured with bacteria, plant roots etc.

Once that is accomplished, the tank does much better over all.

But adding mulm from another tank does that right away. 

Maybe it's the bacteria, not the alleopathic chemicals.......those two have
been at odds for what? 2-3 billion years? 

Tom Barr