Types of hydroponic systems

Aeroponic Sprayer
The aeroponic design is centered around the idea that the roots of a plant should be exposed to the highest proportion of air (oxygen) as is possible. In an aeroponic system the roots are encouraged to grow down into a closed "air reservoir". The roots are bathed in a nutrient solution very often using spray heads driven by a water pump.

An effective aeroponic system keeps roots suspended in air, but doesn't allow the roots to dry.

While the aeroponic system has traditionally been considered an aggregate-free growth method, a lot of flexibility can be gained by using mesh pots and an aggregate medium. In an aggregate-less approach, the plants are held in place by neoprene sleeves that isolate the root chamber from the outside environment, while letting the plant stems pass through.

This method is by far the most equipment centric, but produces growth volume in amounts greater than any of the other methods.

Requirements

 * Containment bin (reservoir)
 * High-count cycle timer (short duration bursts of runtime)
 * Water pump
 * Spray heads
 * Water/return tubing

Aeroponic Bubbler
Here, instead of using active sprayers and a water pump, an air pump is used to create bubbles in a nutrient mixture. The roots are irrigated by the "cast-off" of bubbles rising to the surface and popping.

Requirements

 * Containment bin (reservoir)
 * Air pump
 * Air tubing
 * Air diffusing device(s), such as air stones

The advantages being that there are no spray heads to clog, and aeration is superb as oxygen is flowing through the nutrient.

The disadvantage is the noise, and it needs large bubbles to produce the spray. Also, the level of the nutrient needs to be precisely metered to keep it close enough to the roots

Aero-drip
This is a system that I have seen that I do not know the proper name for. Here's how it works:
 * 1) Plants are placed in a moderately absorbent aggregate. LECA is suitable, rockwool is not.
 * 2) Nutrient is continuously fed from the top of the plants, and trickles down through theaggregate, onto the roots.
 * 3) At the bottom of the container is a pool of nutrient. But the aggregate never touches the nutrient solution, as the container is split into two levels, with a mesh barrier separating the two compartments so that the roots and excess nutrient can pass freely into the lower area.
 * 4) Roots are also free to submerge themselves.
 * 5) The system runs continuously

Requirements

 * Containment bin (reservoir)
 * Water pump
 * Drip tubing
 * Drippers/emitters
 * Water/return tubing

Aeroponic Atomizer/Fogger/Vaporizer
Here, ultrasonic vaporizers are used to create a fog which fills the root chamber. It's very low maintenance. There are no spray heads to clog, and aeration is superb as the nutrient bubbles.

Requirements

 * Containment bin (reservoir)
 * Vaporizer (made by such companies as Nutramist)

Lettuce Raft
The lettuce raft system is in wide use for growing low-lying, quick growing crops such as lettuces. In these applications the plants are not even placed in containers, but are inserted directly into the holes cut into a styrofoam raft that floats on a nutrient bath that is oxygenated by bubbles pumped from underneath.

Requirements

 * Containment bin
 * Air pump
 * Styrofoam "rafts"
 * Air diffusing device(s), such as air stones

Full Submersion
The full submersion method negates the use of water pumps. Instead, the plant roots are continuously in a pool of nutrient solution. To provide the necessary oxygen to the roots

Requirements

 * Containment bin
 * Air pump
 * Air diffusing device(s), such as air stones

Nutrient Film (NFT)
A nutrient film technique (NFT) system relies on a constant supply of nutrient flowing in the bottom of an inclined container. Nutrient is introduced at one end of the system and recollected at the other end. The system is inclined just enough to prevent standing pools of nutrient. These systems are best designed shallow and lengthened. For this reason, they are suitable for non-square growing areas.Disadvantages of a NFT system include the tendency of the plants closest to the nutrient injection point to grow the strongest, while plants down the line are exposed to less nutrient solution, and so are less likely to grow vigorously. This issue can be partly addressed by having multiple injection points. Another issue is that root masses sometimes block the flow of nutrient from one end to the onther.

Plants must be rooted before placing into the NFT system

In the other systems, rockwool cubes are in direct contact with the film, and so wick the moisture up to the roots, so the roots are never left high-and-dry.

Advantages of the NFT system are its low maintenance, as there are no sprayers or drippers to clog. Also, a very small pump can be used, as there does not have to be a large volume of nutrient running through the system. The enclosed channels create high humidity in the root zone, while leaving most of the root mass in mid-air. Extra humidity can be introduced with an ultrasonic fogger.

Aero-NFT
This combination system uses sprayers to introduce nutrient into a NFT tube, instead of relying on a bulkhead dumping the solution directly into one end. The ceiling is lined with many aeroponic sprayers.

Ebb and Flow (Flood and Drain)
This is the most common hydroponic system. In this method, the plants grow in an aggregrate medium inside a container. The container is placed into a flood tray that is suspended above a reservoir containing nutrient and pump. Every 3-4hours, the tray is flooded and drained of nutrient solution. Upright tubes open at the top prevent overflow, and holes in the flood tray allow the nutrient to seep back into the reservoir. Between irrigations the growing medium holds moisture so that the roots do not dry out.Requirements: 
 * Water pump
 * Water/drain tubing
 * Timer
 * Reservoir

Autopot
The autopot system is centered around a patented design for a delayed watering mechanism called the Smart Valve. All that's needed is gravity.

Requirements

 * Smartvalve MkII