Pumice
Like

perlite,


pumice


is


a

lightweight,


mined


volcanic

rock


that


finds

application


in


Aquaponics.
Vermiculite
Like

perlite,


vermiculite


is


another


mineral


that


has

been


superheated

until


it

has

expanded


into

light


pebbles.
Vermiculite

holds


more


water


than


perlite


and

has

a

natural

"wicking"

property

that


can

draw

water


and
effluent

water


in


a

passive


Aquaponic


system.


If

too


much


water


and

not


enough


air

surrounds


the


plants
roots,

it's


possible

to


gradually

lower


the


medium's

water

-

retention


capability

by

mixing


in


increasing

quantities
of

perlite.
Sand
Sand

is


cheap


and

easily

available.


However,


it

is


heavy,


does

not


hold


water


very


well,


and

it

must


be
sterilized

between


use.
Gravel
The

same


type


that


is


used

in


aquariums,


though

any

small


gravel


can

be

used,


provided


it

is


washed


first.
Indeed,

plants

growing


in


a

typical


traditional


gravel


filter


bed,


with


water


circulated


using


electric

powerhead
pumps,

are


in


effect


being


grown


using


gravel


Aquaponic.


Gravel


is


inexpensive,

easy

to


keep

clean,


drains
well

and

won't

become

waterlogged.


However,


it

is


also


heavy,


and

if

the


system

doesn't


provide


continuous
water,

the


plant


roots


may


dry


out.
Brick

shards
Brick

shards


have

similar


properties


to


gravel.


They


have

the


added


disadvantages


of


possibly

altering


the


pH
and
requiring


extra


cleaning


before


reuse.
Polystyrene

packing


peanuts
Polystyrene

packing


peanuts

are


inexpensive,

readily


available,


and

have

excellent


drainage.


However,


they
can
be

too


lightweight


for


some


uses.


They


are


mainly


used

in


closed


tube


systems.


Note

that


polystyrene
peanuts
must


be

used;


biodegradable


packing


peanuts

will


decompose

into

a

sludge.


Plants


may


absorb
styrene

and

pass

it

to


their


consumers;


this

is


a

possible

health


risk.
Wood

fiber
Wood
fiber,


produced

from

steam

friction


of


wood,


is


a

very


efficient


organic


substrate

for


Aquaponics.


It

has
the

advantage

that


it

keeps

its

structure


for


a

very


long


time.



Here

are


some


Illustrations

of


systems

just
mentioned.
Drip
System
The

Aquaponic


Drip


System


below

shows


a

simplified

diagram

of


a

drip

system.



The


red


spots


represent


the
plants.


This


type


of


system

is


widely


used

to


produce

plants

in


a

grow

bed

medium.



The


nutrient


rich

fish
water

is


pumped

from

the


fish

tanks


to


provider

manifolds


positioned

above


the


grow

beds.



Holes

are


drilled
into
the


manifolds


and

small


tubing


spickets

are


inserted

into

these


holes


and

glued


into

place.



Drip


tubes


cut