Damn, cool idea putting the sprayers in lid and pump up top (no heat). Never would have thought of it. I always shied away from making [one of those units] with the 1/2" pvc spraybar because of not being sure of the exact height the sprayers would have to sit at, to hit the roots/stems. And once the PVC assembly's glued together (to test it if it's at the wrong height).........
But this method you could adjust the height of the sprayers.
Thank you.