I am a noobie and I need some help.

I have run this system, my design, for the past three years. My rez is a 12 gallon cooler with a 400 GPH pump and 2 aerating stones. I change the nutes about every 10 days. I have a valve to keep volume to upper plants lower than the tomatoes. The rez isn't in the picture, it is all the way right, off the deck and down 18". There is a main feeder tube 1/2" and each plant has a 1/4" tube feeding it. There are no drippers or sprays. It just flows. This has given me hundreds of tomatoes from indeterminate vines. and tons of chard, lettuce and bok choy. I can grow hydroponically. But I failed at indoor DWC.