Re: Allelopathic Chemicals

[AquaServe at aol_com]

I have not received any discussion updates for a week or so for some reason 
so I had to go to the website to view the last few posts.  I will try to 
continue the discussion so please forgive me if this is confusing:

Tom Barr referring to my question about Barley Straw use:
"I never found this to be the case. Does it hurt? No, does it help? Not in 
mytanks.Is it something else yet to sell to folks with algae problems? I'll 
hang onto my money."

My reply:  I cannot agree or disagree because I have not tried it.  However, 
let me point out that the information I have found states that green straw 
should not be used because it will decay and release too many nitrogen 
compounds and actually feed the algae. (You had mentioned you had also used 
green algae).  Also, existing studies point out that barley straw (if it 
works) will not really kill existing algae...only inhibit growth of new algae 
cells.  This may end up with the same end result by not allowing the algae to 
reproduce but it would certainly not be indicated for a preexisting algae 
problem.  I think the potential use (please stress potential) is that it 
could help prevent algae blooms.

Tom Barr said"
"In the literature I've found it had _zero_ effect on hair algae, someeffects 
on Green water type phytoplankton, but this was also correlated withan 
increase in rotifer biomass which eat ..........you got 
it,phytoplankton........I'd a say adding rotifers or Daphnia(these are much 
larger and make greatfish food) would do the same given some time. Rotifers 
are small enough notto get eaten by most fish. Daphnia are much more 
efficient herbivoresthough.  It had no effects on any red alga(AStaghorn, BBA 
etc)."

My reply:  Very true.  Would still wonder what the result would be with 
Daphnia and Rotifers absent.


Tom's Reply to my comment about the study not being conducted on a small 
testing subject:
 "Consider trimming and pruning 2000 gallons. Or doing a 50% water change 
andadding fresh nutrients back etc. Or adding CO2.Personally, I find a pond 
full of rotting straw quite nasty, I'll take someDaphnia or other herbivores 
to do the work(Koi, carp etc)>"


My reply:  I may agree with your comment about nasty rotting straw but again, 
if applied in small amounts in an aquarium, in a filter box, and in a small 
mesh bag..I don't know if it would be any more nasty than existing mulm in 
the gravel bed or peat to a filter, etc.


Tom's reply to my consideration of a testing model"
"Be there, done that.Be careful how you draw conclusions.Folks that claim 
algae control products work well often have algae problemsto 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 thealgae's demise.Adding cultures of exponentially growing 
algae with relative good access tonutrients, light etc and maintaining good 
controls rather than some halfdead algae will tell if something is relatively 
effective or not. I do notthink 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 itget rid of something etc. I never found any effect with any of thes
eproducts. My personal opinion and philosophy: I think folks should get away 
from allthese extra algae killers, controllers etc. It leads them down a long 
paththat does not address the plants at all and cost them more $ in the 
longrun. 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 havea wand. I've said it a few hundred times. Grow the plants, the 
algae will not. Strawdoes not grow plants.Regards, Tom Barr

My reply:

All very good thoughts and information.  I happen to agree to a point but too 
much of a good thing can always be said about just about 
everything...including adhering to the "natural method" of aquarium keeping.  
If something like this could work...or any form of algae control, filtration, 
etc...then it is certainly worth investigating.  I just think it is worth 
looking into with an open but always cautious and questioning mind. In any 
case...sure sounds like a good topic to study for awhile.  Thanks Tom for the 
input.