sweet deal oneman, maybe we can keep our multi wheel grow data together so we can learn from each other....have you considered ventelation design on multiple units? and as for resi design, i was thinking of creating a run off channel under the machine to a shallow central drain res to pump back into the main res (its hard to hav a res that size be lower than the machine so gravity return will not suffice in this case) and just run a 200- 300 gal resi to "un clutter" the system and have uniform results on all my cultures in the same stage of life cycle. i think 3-4resi's can manage the entire place. and need minimum maintanance....aditionally with valves on the resi you can swap resi lines to change the nute combos without ever moving a single thing in your room. kinda like having different mixes on demmand. whats your opinion on that?