Awesome set up. My first attempt at DWC failed miserably due to accidentally dialing the air pump ALL the way down to all 4 buckets. It was with photo clones, just started a thread today about my next attempt ( with autos, half in the dwc, half in coco) which I will be updating when the beans come in. I have been reading everything I can to learn as much as possible before undertaking the next one, but I honestly think that you have too much pressure coming out of your stones rolling your roots around themselves. Thinking the air is creating a horizontal vortex current in your rectangle res and rolling them up on themselves. they still look beautiful up top, and great color and mass below, but they aren't growing that way in purpose. I do hold a degree in wildlife science, but have no experience to speak of about growing other than what I have crammed in to a year of prepping, a month of setting up, and then 3 weeks to murder the beautiful clones. Just my thoughts, but can you adjust the pressure or add a few more hoses coming in the other side of the res to more stones to dissipate, disrupt,and even out the direction of O2 circulation inside a little???
Good Luck. So glad I Found This Site!