Really all you need is a little reservoir, a small water pump, some pvc piping, and some sprinkler supples. You can essentially copy an aerocloner but put it upside down, above the clones. Obviously it would need very little water for very little time, but a simple digital timer lets you set multiple spray points if you want.

that being said, how come you mist so often? I mist about once every 3 days. Stays humid and moist inside. I let them breath for a few minutes once or twice a day. Also, for that much work, why not just build an aerocloner and forget the misting?

just curious.