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algea growth
I have been following the algae discussion and wondering exactly why
high-nutrient/CO2 injected tanks are algae free (in the hands of people
who know what they are doing). The results speak for themselves to some
extent of course - but it isn't clear to me why the algae should die
back just because the plants are happy. I find the low-nutrient argument
much more intuitive - something like "plants have roots and can store
more nutrients so they tolerate low nutrients in the water column better
than algae" - that makes sense. But if there are plenty of macros and
micros and light and CO2 etc etc, what holds the algae back? I like the
allelochemicals argument - but then (as others - meaning Mr. Tom Barr if
I remember right - have argued) big water changes should allow a spurt
in algae production by lowering allelochemical concentrations - which
doesn't seem to happen. It would also make sense to me to argue that by
keeping background algea populations low with manual removal and algae
eaters there isn't the potential there for a major population explosion.
No one would dispute that this is true - would they? - but it doesn't
explain the cases where simply adding nutrients makes problem algae go away.
I guess you could ask similar questions about regular roadside weeds -
do weeds take over in poor soil because they really _like_ poor soil, or
are they just filling in where other plants can't make it? So you
fertilize the roadside and a bigger variety of plants will grow and the
weeds will go away (or seem like less of a problem)? Hmm. Probably true.
But do algea and plants compete directly for the same resources in the
same way that different varieties of plants do?
I've been enjoying the discussions on this list very much - I've been
following silently for a year or so. I have a particular interest in
algae because I have a green water problem that I've knocked back from
pea soup to a persistent but more transparent haze over the past few
months - I'll spare everyone the details of the things I have tried -
all of them suggestions from this list. I'm sure they are all good
suggestions but I have a hard time following them consistently. When I
try to starve my algae (you laugh?) I'm defeated by the junky substrate
I put together when I didn't know any better. I have a hard time
following the high-nutrient regime because I'm nervous that I'll be back
to pea soup if I overdo it. I would also like to have a better
understanding of why it is supposed to work....
I look forward very much to hearing your thoughts on this.
mike