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Re: Yet another plant tank design

> > Kevin Conlin <kcconlin at cae_ca> posted:
> >                            Aeration chamber
> >                         |                    |      
> >           ---------------      Nutrient      ---------------
> >           | _____________   -> Water Flow -> _____________ |
> >           | |           |____________________|           | |
> >    |      | |                                            | |     |
> >    |    -------                                          | |     |
> >    |--- |     | ------- Water Line --------------------- | | ----|
> >    |    |     |                                          | |     |
> >    |    |______                                          | |     |
> >    |      | |   Powerhead                                | |     |
> >    |----- | | ------------2" Gravel -------------------- | | ----|
> >    |      | |                                            | |     |
> >    |_ _ _ | |_ _ _ _ _ _ _ Fine Mesh _ _ _ _ _ _ _ _ _ _ | |_ _ _|
> >    |                    2" Root Growth Area (no gravel)          |
> >    |_____________________________________________________________|
> > Plant roots grow through the fine mesh into the aerated nutrient
> > solution circulating below the gravel.  [snip]

> Earle Hamilton <ehami at sunny_ncmc.cc.mi.us> responded:
> [snip] I see two problems however.  
> If the roots are going to be encourage to grow under a barier, it will be 
> difficult to remove the plants without them getting tangled and torn 
> off. These torn off roots would decay eventually but that may not 
> be all bad.
> My real concern in the need for co2.  We don't want to aerate as much as 
> we want to reduce co2 removal.  Kevins design would be less expensive 
> than earlier designs and would be worth a try for somebody.  
> Unfortunately, to be a valid test would require all sorts of controls and 
> measurements but it still looks like something worth trying.

Kevin, good design.  I'm doing this now.  I am very happy with it.  I
would do the same thing again.

Earle, you are correct.  The roots grow into the space below, and are
broken off when plants are moved/pruned.

My system is the following:
                                                               oooo
|                                                           | o    o
|~~~~~~~~~~~~water level~~~~~~~~~~~~~~~~~~|      |~~~~~~~~~~| o   /o\
|                                          \    /           | o  | o |
|                                           |  |            | o  | o |
|                                           |  |            | o  | o |
|                                           |  |            | o  |___|
|                                           |  |            | o nutrient
|------------------------substrate----------|  |------------| o   rich
|                                           |  |            | o  bottle
|------------------------egg-crate----------|  |------------| o
|                 ( o p e n   s p a c e )   | oooo          | o<-.
|-------------------------------------------| o|------------| o  |
                                            | o|              o  |
                                            |  ooooooooooooooo   |
                                            |  |     airline tube/
                                          (to sump)
With this setup, I dissolve my Dupla tablets into the "nutrient rich
bottle", and I put the bottle on TOP of my tank and let gravity dump 
the solution directly into the substrate.  Simliarly, I can drain water 
out of the substrate (to test nutrients, whatever) by lowering the 
bottle below tank water level.

I can take the airline tube and put it directly in my sump (under the
tank), and I have a really good UGF with no power head (It's incredible!
It's magic!).  I can put the sump above the tank (or add another 
container of water above the tank) with the airline tube in it, and I 
have RUGF with no power input.  You get the idea:  I'm a penny-pinching 
tightwad that doesn't like to pay the electric bill.  :^>

BTW, in addition to a low electric bill, I have very low surface
disturbance (I want to add CO2 later).

Actually, I wanted to set this system up for research and to allow for
circulation of high nutrient water in the plenum below the substrate,
and actually installed TWO airline tube networks in the space below
the tank.  The following is the overhead view:

  -------------------------------------------------------------
  | ooooooooooooooooooooooooooooooooooooooooooooooooooooooooo | 
  |o |                         <|                 o        <-o| 
  |o V                                            o          o| 
  |o                ooooooooooooooooooooo        _o          o| 
  |o               o>         |>       V o      / o\         o| 
  |o               o                     oooooooo   |        o| 
  |o               o^         <|        <o      \__/         o| 
  |o                ooooooooooooooooooooo                    o| 
  |o                                                         o| 
  |o                                                       ^ o| 
  |o->                         |>                          | o| 
  | ooooooooooooooooooooooooooooooooooooooooooooooooooooooooo | 
  -------------------------------------------------------------
     
The "outside" square is intended to be my "input" line, where I will
dose the plenum with nutrient rich solutions (and I've thought about
warm/hot water, but haven't tried that yet).  The "V's" are diffusers
into the plenum from the airline tubing, and I established current by 
where they are placed.

The "inside" tube is intended to be an "output" line, where I can 
siphon water out of the substrate.  The current flows in the oppossite 
direction and is inside the tube square to cause a "whirlpool siphon" 
effect in removing the water (it does spin in the opposite direction 
of the "input" line, though).  My thought was that I could put a pump 
in between both lines and force a strong current within the substrate 
with low net pressure for either RUGF or UGF.

This is a 180 gallon tank, and I have full view of the bottom.  The
plenum is supported by egg-crate, covered with 2-3 layers of nylon 
screen.  The substrate is 2 mm sand (sandblasting gravel), and layers 
of peat and vermiculite in the bottom 1/3, if you were wondering.  
The tank is well-planted, thanks to George Booth.  (HEY, GEORGE!  
Nothing died!  My CABOMBA HAS RUNNERS!  I didn't know cabomba used 
runners!?  I was worried about the Alnathera, but it's doing fine! :^)

The setup was incredibly cheap (except egg crate was $14 for a 2x4
foot sheet), and it is incredibly cheap to operate (gravity).  Most
of the time, I simply do nothing:  I dose nutrients every now and
then, but otherwise leave the tubes turned "off" and no flow occurs
in the plenum.

BTW, the root growth is AMAZING, and I have only 1.22 watts/gallon 
of light (it's still a new tank, though: less than two months).

I have already designed a commercial version of the same system that
I would use to propagate plants at a commercial level.  The only 
difference is that I have made modifications to the 
framework/infrastructure to allow me to mechanically "prune" off 
roots that grow through the screen and into the plenum.  Thus, the 
plenum can be directly accessed for maintenance or cleaning.

I intend to experiment heavily with nutrient-rich substrates and 
nutrient poor water columns (impacts on plant growth, algae growth, 
etc).  Further, I would like to experiment with warm water doses 
and peat water doses (crash that pH!) directly to the substrate.

I originally conceived this framework to combat my worries with peat:  
I had never used it before, and didn't want an anaerobic substrate.  
(Now, I'm starting to think an anaerobic substrate can be a good thing).
However, at the first sign of anaerobic bacteria, I can very easily 
inject air into the plenum to halt those processes, or inject O2-laden 
water for the same effect.

[embarrassing part]:
I've heard of people that come up with ideas, use them, and somebody 
else patents it, and the author can't use it anymore (the courts don't 
care who the author is).  I really like this design, and have 
commercial plans.  I don't care who uses it, I just want to be sure 
*I* can continue to use it (I don't want anybody to patent it and tell 
me I can't use it anymore).  Is this an issue, or am I just paranoid?  

I'm not paranoid!  I'm perceptive!  Who said that?  What?  I hear 
voices, but I don't do what they tell me.   :^>

But I don't need affirmation, do I?   ;^>

--charley                           Fort Collins, Colorado USA
charley at gr_hp.com	or	charley at agrostis_nrel.colostate.edu