hi everyone, been looking thru this grow.. ive done a few dwc and just about to start I think my 5th.. anyway ive run into some of the same problems you have in the past. What i noticed in the beginning of your grow is that you got that your babies in that wool cube thingy (cant remember the name of them now) anyway the point is i noticed that if you use the hydo rocks, stick to just the rocks. Ive moved clones from those dirt pucks and put them right into the rocks with the puck still holding the the root ball. Not good, im sure if you read up on it you'll see this causes root rot (browning of the roots) so damn easy. The cube isnt suppose to be wet alll the time since it will hold water, mold is easy to accumulate. Im thinking this is why your plants seem to be on this up and down rollercoaster the plant is fighting the roots getting rotted.
Also, I would say regulate your water temperature, keep it chilled, the warm water is not only retaining less oxygen in the water but the warm humidity coming from the mist your dwc system is making under the top of the container.. this space where your roots are coming out of the rocks but havent made it to the water yet are sitting in that warm misty humid area and getting rotted also you can see this by the top of the roots are brown and not so much the bottom portion.. As of now theres not much you can do but ride it out and keep the water cooler but change the temp progressivly any sudden change is going to stress your babies and possibly put them into even more jeopardy =..( anyway do some reading on this stuff and tweek your dwc its the way to go if you can get good at it..gl ill keep watching the progress