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Re: [APD] Re: High water evaporation in a planted aquarium -- or WhoChanged the Water?
The water change methods are practical and sucessful -- I
use one or two of them myself -- One or two? Well it
depends on how to differentiate one method from another.
But no-water-change (or more accurately,
prolonged-deferred-water-change) methods can be done
sucessfully too. Just listen to or read some of those that
have done it, Diana Walstad's account being the most
comprehensively written and, imo, authoritative.
You don't need pure H2O to make it work, you probably don't
need RO to make it work -- of course, if you have
abnormally high evaporation rates, then that taxes the
Large frequent water changes add lots of "forgiveness" to
you aquatic system. Slow growth systems do the same thing
in a different way. But, by golly, they are both practical
and the slow grows are, for me, much easier to pull off.
Sunken gardens are a lot like terrresterial above-water
gardens -- lots of ways to grow successfully -- certainly
more ways than you can count on one hand.
I would guess that most of the practical ways for keeping
freshwater fish tanks can be applied or adapted to growing
As for completely closed synthetic ecological systems,
well, even the humans snuck out for pizza, didn't they?
And while we're off the subject ;-), I'm amazed that no one
has actually offered data on water in a bucket instead of
hypotheses about what the data would be -- This has been
going on (or off and on) for years. It's a paradigm of
nonscience on APD and yet it's one of the easier to answer
of all the empirical questions ever posed on APD. I'll
wager that the master of bucket gardening, Ricky Cain,
knows the answer and laughs like Santa in December when he
reads the hypostheses.
I once worked as a tilesetter and that line of work
involves putting water in buckets. So I know the answer
too, don't you?
At times like these, thinking fondly of the G. E. Moore and
--- Robert T Ricketts <rtricketts at erols_com> wrote:
> RO may be a lab
> standard, but RO,
> like tap, is not a single purity standard. It depends on
> the operation of
> the membranes and the rejection rate. The "purity" (poor
> term in practice)
> is defined solely by the resistance/conductivity/TDS of
> the output water.
> The fact that it has been through an RO unit does not in
> itself define the
> purity at all. If you wanted the closest you can get to
> "pure" water, you
> would want WFI (water for injection), which itself is
> prepared from high
> resistance RODI. But that would be a complete waste for
> tank use IMHO, and
> astronomically expensive. The color of the water in a
> white bucket has not
> been determined either - because the bucket would
> contaminate the water.
> There are some other assumptions behind the statement
> that should be
> considered as well. The first was discussed in the first
> paragraph. The
> next assumption would be that the hobbyist never ever put
> in more
> fertilizer/supplement than the plants would uptake, and
> that the livestock
> in the tank never ever contributed anything to the water
> which the plants
> could not and would not uptake (anyone know of aquarium
> plants which use
> phenols?), nor would such materials ever be added with
> feeding. Without
> absurdities such as full spectrophotometer and flame
> photometer analyses,
> followed by literature searches to find any negatives
> associated with the
> materials identified, you will never know beyond the
> crudity of hobby tests.
> Even Diana Waldstad does some water changes, although at
> very long
> intervals. A closed ecosystem has not yet been done
> successfully for
> indefinite operation, and an aquarium with routine
> supplementation and
> feeding of livestock is far from a closed system.
> I personally can find no valid basis for operating tanks
> without regular and
> significant water changes, in part for the reasons Tom
> Barr has presented so
> many times on this list, and in part for
> removal/reduction/dilution of all
> the undetected materials added to or produced in the tank
> Others may do as they will, but I hope that they do so
> with knowledge and
> acceptance of their own assumptions.
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