Turn on and inspect for and repair any leaks, both air or liquid.FILL CYCLE
Pump comes on and pressurizes the manifold, initiating the emptying of the reservoir up the tube and into the Flood and Drain unit, as well as the bubbling of the air stone in the DWC unit. This continues until the reservoir completely empties or equilibrium is reached between the opposing forces. It can be "tuned", and will be discussed seperately. As the reservoir empties, the bubbles will be redirected, largely, up the tube and into the bubbler rather than the air stone.
The greater the resistance from the air stone, the faster and more completely the reservoir will empty.DRAIN CYCLE
Pump goes off and the water that has evacuated the reservoir returns under the force of gravity. The returning nutrient pushes the air up and out, into the manifold, and out through the DWC air stone as well as any other leak available. The bubbling of the air stone will reduce as the weight of the returning nutrient diminishes, until all of the nutrient returns or an equilibrium of the opposing forces is reached. This can be easily tuned as well.
Please see video for demo of unit w/DWC only as a vent -
Please see video for demo of reservoirs only- TUNING
Tuning is achieved by varying the opposing forces, such as gravity and air pressure. Generally speaking, gravity affects various "thresholds", while air pressure affects rates and the ability to reach the thresholds or a state of equilibrium. At least in my understanding and my ability to explain same. Lets just say, it's a balancing act.
The effects of gravity can easily be varied, and observed, by increasing or decreasing the height of the planters w.r.t. the reservoir or by varying the depth of the air stone in the DWC unit.
The effects of air pressure, acting against gravity, can be regulated by the porosity of the air stone in the DWC unit, by varying the depth of the "self tapping screw valve" in the manifold or reservoir lid, or any other method of controlling the "air tightness" between the air pump and the reservoir.
Using air tightness only, one can overcome the issues with the slow drain rates regardless of pump used, as long as it can supply enough air and pressure that is. With the DWC unit eliminated, the excess air will simply vent out the screw valve thingy.
NOTE: Only one complete system can go onto any one individual pump because of the pressure loss that will occur when/if the reservoir empties. Any slower systems will stop filling, and start draining, when the first one starts bubbling. One larger, shallow reservoir would be preferred over multiple reservoirs in larger systems.