[Paul Perkins]

Thanks to both of you for saving the lives of 24 lettuce seedlings by telling me not to drown them (which process was already well underway as my nutes were right up to the top of the tubs). I've dropped the nutes level so that the netpots are sitting just barely in the solution and will check and adjust for overwicking periodically. In hindsight, rockwool was not the best choice for DWC because it retains too much water vs. air. Will try the coco chips next.

GPS, thank you for posting your extremely impressive CAD drawings. Yes, indeed, your system (except for the inner recirculating tube) is virtually identical to what I had mind -- down to my plan to "go vertical" with 3 levels with OSB on 2x6 vertical supports with 8" sidewall frames in a 12' x 20' greenhouse!

Thanks again!
Paul