NFT (Nutrient Film Technique) - A
method of growing plants in which a thin and even film of aerated
nutrient solution flows down a channel into which the roots of the crop
are suspended. It is very important to filter the water well
before sending it to an NFT trough since fish waste in the trough and
on the plant roots will negatively impact the plant's growth. NFT
aquaponics requires separate solids and bio-filtration. While the
reduced amount of water needed to fill the system may seem like a
benefit, it can mean greater temperature and water quality fluctuations
in a short period of time.
DWC (Deep Water Culture)
- DWC is often referred to as Raft where the plants grow suspended over
a tank of water in which nutrient rich water flows with supplemental
aeration. In most situations filtration needs to occur before fish
water is sent to the raft area of the system.
CHIFT PIST (Constant Height In Fish Tank Pump In Sump Tank) - Maintaining
a constant volume/height in the fish tank with a sump tank at the
lowest point and a fish tank at a higher point. The pump lifts water
from the sump tank to the fish tank and water flows from the fish tank
to the grow beds which drain back to the sump tank. CHOP (Constant Height One Pump) - Basically the same
thing as CHIFT PIST. With CHIFT PIST there has not normally been a
distinction between the variation where the fish tank drains back to the
sump directly and the pump pumps to the grow beds and they might drain
to the sump or the fish tank. With CHOP it was normally assumed that
the fish tank got the water from the pump and drained to grow beds which
drained to the sump. CHOP2 - The variation of CHIFT PIST where both
the fish tank and grow beds drained to the sump and the sump pumped
to both the growbeds and fish tank Flood and Drain- The plant growing
space is allowed to flood and then drain either by the use of a pump on a
timer to fill the bed and then allow it to drain while the pump is off
or by the use of a siphon or other intermittent outflow device where the
bed is constantly filling and then the siphon will drain the bed
quickly.
Advantages: providing ample oxygen to plant roots and bio filter
bacteria without the need of extra aeration. Many plants like some dry
time especially if the water is not super aerated.
Disadvantages: Water level needs to fluctuate in the system to
provide the water for flood and drain. Flood and drain offers more
media to air than media to water interface which can have an exaggerated
heat exchange effect on water temperatures. Ebb and Flow - The same as Flood and Drain except you
are usually pumping up through the bottom of the grow bed and then when
the pump turns off, you are draining back down through the pump.