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Re: [APD] Cycling

Several messages back, Stuart Halliday mentioned Diana Waldstad's theory
that bacterial bioflters out-compete plants for the first nitrification
bacterial energy source (ammonia) and are therefore somehow undesirable or
even detrimental on planted tanks.  That theory has figured in some further

IMHO, Ms Waldstad might do better to test more before publishing theories,
or at least noted that there was no confirming data.  Science is about and
based on testing and evidence, hard data.  There is a great deal of art and
design in planted tanks, but without the underlying facts being accurate,
the system does not work.

I have played with biofiltration (aerobic and anaerobic bacterial, plant,
and chemical - even though that last is not technically biological
filtration) a lot in my tank-keeping. I also have long used the practice of
operating a number of "spare" filters on my tanks, not from need there on
any particular tank, but to have mature biolfilters available when needed or
desired for new setups.   It did not take rocket science or any advanced
math to notice that the best 'spares" came from fish-only (FO) tanks.
Spares from heavily planted tanks proved to be well-inoculated, but in no
way "mature" in handling even half the bioload of the donor tank on which it
had been operating.  That was enough to awake my interest and prompt a bit
of bare-tank testing.  That confirmed the casual observations that the
filters had the right bacteria for oxidizing ammonia and nitrite to nitrate,
but sorely lack sufficient colony size to avoid detectable ammonia and/or
nitrite in newly set tanks.  This observation was mentioned in one of my
articles and has been relayed many times in forum posts.  Quite a number of
folks have agreed with that observation.  No one to date has opposed it or
presented opposing data. I have to conclude that that theory was reached
without observation of the basic effect, and when real-world tested, fails
to support the original theory.  The data I have seen tend to support an
opposite theory, that healthy plants easily out-compete bacterial biofilters
for ammonia, with the corollary that while nitrification bacteria do survive
as persistent colonies in heavily planted tanks, those colonies are
insufficient to support even half the bioload of the tank on which they

Thinking about tank biology is a good thing.  Proposed theories of operation
and tank function do need to be tested before being presented, or at the
least should be labeled as to their untested and unconfirmed status.
Otherwise myths are created and propagated endlessly.  IMHO, that particular
theory is mythology.

In other words, test first, talk later.


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