Connect 2 reservoirs with 1 hose, and form a siphon. when the waterline of 1 res goes down, the second res will fill it, and vice versa. this can be good for mixing nutes or adjusting ph over a period time as well. the 2 res's mix when their water levels change, so there is diffusion.

wondering what you all thought about this, I can lay it out in a diagram as well.