I'm surprised not to see aquaponics not mentioned in this section.

Like most people people think aquaponics is hydroponics. It is not.

Aquaponics is a sustainable method of growing food by using waste from fish to produce a cycle of production.

Benefits :

Uses 10% of the water used for conventional gardening
No need for fertilisers or pesticides,
No soil used
Organic
Food can be produced in abundance

If you are interested then we are trying to expand the knowledge in the UK and have a website called Aquaponics Advice and Products in the UKadmin. This will give you plenty of information.