Heating to around 200 degrees F, ozone, ionization device kills by copper and silver ions. Chlorine or bromine injection. Filtration via membrane filters. Rock wool cutlture. Product of the burning of coke, basalt, limestone and possible slag from iron production.
Benches contain the system or on floor.
Really same as ebb and flow except in trough. Better air circulation. Whole firm recirculation. Advantages and disadvantages. Water applied 5 to 6 times per day . . . as plant needs.