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Re:allelopathic chem's

> Although this does not really fall under the category of allelopathic
> chemicals, I posted a question/request for anyone with experiance/knowledge
> of the use of barley straw to control algae.  I know this subject has come up
> before but I do not believe it has been explored thorowly enough with regard
> to it's application in the freshwater/planted aquarium.

I've used this, I've used fresh barley straw also. Never did a thing.
I had a few other folks I know that tried it, same thing. We keep good tabs
on NO3, CO2 etc.

> I am writing an 
> article on the subject and would love to hear other's thoughts or opinions on
> the efficacy of barley straw and it's use for algae control.  Studies have
> been conducted with the majority of results being positive with respect to
> algalstatic (not algalcidal) use.

I never found this to be the case. Does it hurt? No, does it help? Not in my
Is it something else yet to sell to folks with algae problems? I'll hang on
to my money.

In the literature I've found it had _zero_ effect on hair algae, some
effects on Green water type phytoplankton, but this was also correlated with
an increase in rotifer biomass which eat ..........you got it,

I'd a say adding rotifers or Daphnia(these are much larger and make great
fish food) would do the same given some time. Rotifers are small enough not
to get eaten by most fish. Daphnia are much more efficient herbivores

It had no effects on any red alga(AStaghorn, BBA etc).

> These tests have been conducted on larger
> bodies of water and not small testing subjects (i.e.- aquariums) to the best
> of my knowledge. 

Consider trimming and pruning 2000 gallons. Or doing a 50% water change and
adding fresh nutrients back etc. Or adding CO2.

Personally, I find a pond full of rotting straw quite nasty, I'll take some
Daphnia or other herbivores to do the work(Koi, carp etc)

> The implementation of a testing model would be very
> interesting (I have developed such a model but have not put into action yet).
> Perhaps someone here would be interested in helping to conduct such a
> controlled study?

Be there, done that.
Be careful how you draw conclusions.
Folks that claim algae control products work well often have algae problems
to start with. Only by controlling the cause and then inducing some algae,
will tell much about a product or what's going on.
You may attribute the cause to something that had nothing to do with the
algae's demise.

Adding cultures of exponentially growing algae with relative good access to
nutrients, light etc and maintaining good controls rather than some half
dead algae will tell if something is relatively effective or not. I do not
think the studies accounted for that in some cases.
Aquarist's tank's that have algae to start with are problem tanks generally.

There's the simple practical method, add it to your own tank and see if it
get rid of something etc. I never found any effect with any of these

My personal opinion and philosophy: I think folks should get away from all
these extra algae killers, controllers etc. It leads them down a long path
that does not address the plants at all and cost them more $ in the long
I have grown more species of FW algae and exposed my tank's to many species,
but I do not need these products.
I can honestly say I never will need them either.

But folks say, "well that's _you_". I don't do anything magic, I don't have
a wand. 
I've said it a few hundred times. Grow the plants, the algae will not. Straw
does not grow plants.

Tom Barr
> Duane Clark
> AquaServe Aquarium Publications.