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Re: Sand
> Date: Mon, 5 Feb 2001 11:43:56 -0500 (EST)
> From: Ivo Busko
> I am now convinced that for long term stability we need
> to provide ample pore space throughout all the substrate
> depth...
Would that be long- term "stability", or merely ease of maintenance?
One thing's for sure - without intervention on our part in some way, the
substrate will eventually peter out and lose its viability. Nutrients are
depleted and must be replaced, but how you chose to do it provides the
direction of your approach.
In nature, the replenishment is provided by such mechanics as turnover and
build- up. A river's bottom can be washed away in a flood, stirred up in a
storm or simply replaced by sediment. Lakes are obvious choices for
deposition, but the shallower waters near the shoreline can be affected by
storm action also, mixing and turning some. Land- based run- off can also
provide fresher materials and a new supply of nutrients.
If it came to blows, you couldn't even say that "natural" substrates have
any _real_ long- term "stability", either.
Since we don't find it as convenient to replace our bottoms with such
regularity, we devise easier methods. Manual fertilization is *certainly* an
option - works quite well for everything from farms and gardens right down
to the tank. A convective flow set up to circulate through a gravel
substrate is really only nothing more than "automated" fertilization,
dependent upon taking the nutrients from the water (which you've added
_anyway_, in one form or another) and sequestering them in the substrate.
Just another method.
> ...some people also report that they get good results with fine grained
sand.
> I wonder for how long they get those results though, and would like to
hear
> from people that have kept sand-based substrates for a long time, say
> more than 2-3 years, without facing compaction/anoxic situations.
I can only personally comment on lengths up to about 4 years, which is the
longest I've ever been able to keep a tank in the same position. But that
was by necessity of Life in general, and nothing to do with the tank
itself...
-Y-
David A. Youngker
nestor10 at mindspring_com