I'm not trying to be a negative in any way I figured I'd just give you a heads up on my experiences with the waterfarm 8 piece setup.
From the beginning I had issues with the lower branches becoming too wet and dying off also slowing down the veg process. I'd recommend using some kind of panda plastic or some other material to cover the tops of the buckets during earlier stages of life. This will also help keep algae from forming on the rocks from being exposed to light.
Another huge issue I have with this system is how are you supposed to track nute levels and flush the system? I tried flushing once and took everything apart and cleaned it all but it was one of the biggest pains in the ass I have dealt with when it comes to growing. And I hate how I can't keep track of the nute levels as I believe that to be the culprit for the problems I'm experiencing now.
Now I'm now about 2 weeks from harvest time, up until about a week ago things were going pretty well with the exception of the above mentioned problems. But that's when weird things started happening, some leaves started turning yellowish and dying off, while some of the plants were doing fine. Now about half of my plants have lost 3/4 of all their fan leaves due to them dying and i'm going to have to harvest early. The other half of the system seems to be doing alright and the buds look pretty good.
Again, I'm not trying to be negative I just want to share my first, and last experience with the waterfarm modules. I've since built some homemade rubbermaid containers for moms and those were 1/3 of the price and have given me 0 hassle. I've also been using an aeroflo system and I cannot reccomend that enough, easiest system i've ever used but kinda pricy.
Edit: These 8 plants were under 3x 400w hps hortilux, given a bc series nutes, with additives like hydroguard, hygrozyme, koolbloom, sweet, purple maxx, gravity.