Wouldnt leaving some soultion in the bins with an air stone essentially be DWC? Not that it matters just curious. Also, I was thinking that it would be a bitch to get the solution out of the bins with the plants in them come res change/final flush time.

So all that said, do you think it would be better to design the bins to drain out completely or to leave solution in there with an airstone? Either one would require a complete redesign so I am open to all options.