EC and ppm are basically the same. They will each give you an idea of how much fert is in the water. You're right about conductivity and ppm is parts per million. I don't know what a good EC numbers are like but ppm range is usually 500-750 when their small and up to 1500 when their big. You add fert to keep close to those numbers throughout the grow. I'd paint the lid black if I were you, but that's container's wrong. If you do this right, 8 plants will quickly outgrow such a small container. For 8 plants you can use 5 gallon buckets seperately or put two or three plants in large tubs. 8 plants done right in DWC can easily take over a small bedroom if done right. But you've go to do it right, use the right fert, don't overdo the nutes, average temp 75F, give airflow, lots of air to the water with your pumps. Best of luck. Any questions, just ask.
polishpollack Reviewed by polishpollack on . First Grow OP. FEEDBACK PLEASE ! Ok here is the deal, I am currently getting my hand on all the material required for a perfect hydroponic grow, but due to my lack of experience in this domain I am not sure where I stand in terms of quality and quantity and I could use your help. So for what is worth here goes the list of what I have : 1- A hydroponic grow garden system which includes a black reservoir with a white Lid (14"x7.5"x5"). 8 plants. Air Pump 4" Air Stone Air Tubing Net Cups Rockwool Cubes Plenty of Rating: 5