Re: donut/dry land tanks etc

[Charley Bay <charleyb123 at yahoo_com>]

Interesting thread and thoughts, since many on this
list tend to call themselves "aquatic gardeners".
Hmmm... maybe there should be an organization for
that or something.  ;-)

I tend to be in that category too... I'm gardening,
horticulture-style (the individual plant is
significant), and I just happen to throw fauna in
there to keep things intersting (and the plants tend
to do better as a result).

From that standpoint, many of my plants happen to be
fully aquatic... but there are some really nice 
plants that are marginally aquatic, or even downright
terrestrial.  I throw pathos and spider plant into
many of my tanks to establish a root system, and
often forget to take them out (I forget to water them
if I take them out).

While I am most intersted in the plants (after all,
plants are people too ;-), I prefer to keep critters
in an environment to which they are biologically fit.
Since I get lots of breeding in my tanks, I feel bad
when I find the occasional fry shredded through a 
powerhead.  So, I've migrated to circulation and
filtering styles that are more "gentle", although
I like very violent current (and the fish seem to
also).

For example, this is a design I've been experimenting
with (view this best with courier or a fixed-width
font):

  |                             ...        |
  |~~~~~~~~~~~~~~~~~~~~~~~~~~~......       |
  |                          ......./~~~~~~|
  |                        ......../       |
  |                      ........./        |
  |                   .........../         |
  |               ............../          |
  |           ................./ __        |
  |       ======================|PU|       |
  |........................../  |MP|       |
  |........................./   |  |       |
  ------------------------------------------

It looks like the substrate takes up most of the 
volume, but that's only true on the smaller tanks 
(30g or less).  At 70g or 180g or bigger, the 
substrate is actually a reasonably small percentage
of the tank.  The tank is thus divided to two sides,
with the "main" tank on the left and plants through
the substrate, up the slope, and emergent through
the top.  The substrate breaks the water surface,
so I don't have fish jumping one side to the other
(the fry stay on the left side with the plants, 
and are not drawn into the pump).

The right side is an isolation tank, a sump, or even
a hospital tank.  Theoretically it can be pretty
small (you just have to be able to get your arm
down there to get to the pump.)  If it's really
small and the wall is vertical, then it's the same
as the in-tank sumps we've all seen.  I've angled
the wall in the sump because the goal of the tank
is to give deep-enough substrate for the plants, but
wherever possible, use your space for water (that's
your buffer).

Because of the slope, the fish on the left side can
pick their territory too (bigger fish at the deep
end, the fry in the shallows).

I modeled this after some threads I've seen in reef
tanks, where the goal was to get a lot of water
movement (many stoney corals need heavy current, or
they grow thin and fragile).  Those systems tend to
go for actual waves hitting a beach head (which you
could do here, if your substrate sticks out the top
far enough).  In this setup, the sloped divider is 
egg-crate mesh, lined with two layers of screen.  
Amazingly, there is *no* substrate "leaking through"
into the sump (I've tried 2-4mm sandblasting gravel,
vermiculite, flourite, and peat). In actuality, the
whole slope allows for water percolation from the
left to the right side.  A pump in the sump forces
water to the left side, and I get a lot of force
because I don't lose any energy going uphill like
when my sumps are under the cabinet.  I emphasized
the left side's water level is higher than on the
right because the pump is pumping to the left side,
but it's actually not so pronounced in reality.

This gave me what I wanted:  aquatic, bog, and 
terrestrial plants in their own environments; no
shredded fry on the left side; lots of water 
movement with a small/efficient pump, where I 
don't have to worry about frequent cleaning of
the pump filter; an extra tank for the bully that
needs to reflect upon his actions.

Literally, the sloped substrate is my mechanical 
filter, just like you have on beaches (fresh water
inland, forced there from the ocean after the 
salt and other particulates are removed).

IMHO, don't under-estimate the value of a strong
current.  I've never seen algae take hold in strong
current in my tanks (we all know it's possible, but
I've not had that problem), and the fish can handle
a *lot* of current (those fat lazy-looking corydoras
have no problem in a *really* violent current, and
they seem to enjoy it because that's where they 
hang out).

If I get to build a house (we can all dream), I'm
designing one based on this design.  The tank will
be built into the wall, but only the left-side will
be viewed from the sitting room (the right side
sump will be hidden).  I'm also thinking about a
setup where the front of the tank is "deep", and
the back of the tank is the sump (the back side is
actually the slope to land, not a tank wall).  This
has the advantage that the whole tank can be viewed,
but I think you'd really need a minimum of 24"
front-to-back to make that work (not a problem if
the tank is built-in).

If you've suffered "broken siphon syndrome" or a host
of other plagues from tanks with drilled bottoms or
circulation/filtration systems that are somewhat
sensitive to water level, an appeal of this design
is that it's contained and no matter what happens,
it's not on your living room floor (that's not a
metaphor).

YMMV.  ;-)

--charley


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