This is a recycle set up using Canna nutrients made for coco medium: "Coco 1-0-1" and "Coco 1-4-2. I use 275ml of each in a 20 gallon reservoir of distilled water I got from a self serve water station. The solutions were mixed separately in the reservoir. The reservoir pumps water to each plant via a tube and sprinkler head for 15 minutes every 24 hours. Excess water drains from the pots to the bottom of the bucket and out a tube to a PVC pipe that drains back to the reservoir. The reservoir will be changed out every 2 weeks and next time I may use separate reservoirs for each solution. Buckets are wrapped in black plastic to block out light which may lead to algae growth. That is why the reservoir is dark plastic. Additionally two aereator stones run oxygen into the reservoir from an aquarium pump to keep the water oxygenated when it arrives to the plant. This also inhibits bacterial growth.
Two week change out also avoids changes in pH which I like to keep at 6.5 with the help of a "pH down" solution. The coco medium holds nutrients between watering and is resistant to compaction which will smother the roots. The system is surrounded by cheap reflective mylar and that will be replaced in a couple of weeks. I could get a lot more sophisticated but simplicity rules for now. It’s all trial and error. 
Strains are: "Sour Diesel" and "Northern Lights". There are extra plants in pots of soil in the middle because I ran out of space in another room. Plants in the other room were sown before I set up the hydroponics. I will move them when the hydro plants get too big. Plants are under a Metal Halide high intensity light for 20 hours on/ 4 hours off. Lighting and duration will change when the plants are 15 inches high. Then they will be under High Pressure Sodium Lights for 12 hours/day and in complete darkness. This will prompt the plants to go into flowering. So far So good.
