Howdy RFheavy, I put the drip feeder tube in the net pots right at the bottom of the cubes on a slightly down hill slope (to try to discourage the root from growing into the tube) just where the stream will 'wet' the bottom of the cube. This has seemed to allow the roots to grow down into the reservoir. Once the roots have grown into the reservoir, the circulation pump can be turned off, if one wishes, but the constant flow does aid in circulating the water and keep the roots wet. I do turn off the pump if it becomes clogged and rely on the air stones to give some circulation.
Good luck with Your grow.