Recirculating direct water culture systems (also known as RDWC) use a reservoir to provide water for multiple buckets. Traditional methods using unconnected buckets require individual testing for pH and conductivity factor (CF). This has led to innovations that have seen the removal of air stones in favor of connecting multiple buckets together and recirculating the water. As the water is reintroduced to the bucket it is broken up and aerated with the use of spray nozzles. Constant recirculating oxygenates the water and ensures a good mix of nutrients CF and stabilizes pH throughout the entire system so testing is required only at one point, which would be at the 'Tub' like reservoir. The deep water culture system requires adequate water + oxygen nourishing solution.
The solution is oxygenated (possibly near, or equal to, oxygen saturation) from an air pump combined with porous stones. With this method the plants may grow faster because of higher amounts of oxygen that the roots receive, versus other forms of deep water culture.