Ok, here is my setup I'm going to use right now.
1 - 5 gallon bucket, along with 2 - 4 foot sections of pvc pipe and a pump.
Basically I cut the PVC into two 4 foot sections, then I drilled holes every 6 inches to put the rockwool cubes in, sealed the far end up with test caps. For the water flowing on the inside, I connected 2 - 1/4" pieces of hose to the pump. In the 1/4" hose I took my smallest drill bit and drilled holes in the hose evey couple inches and placed it inside the pvc. The water comes out the pump goes up the tubing and gets sprayed out the hose and runs back to the 5 gallong bucket.
Don't know if I'll run it constantly now or wait till the roots are formed and just keep the rockwool wet.
Remember I'm using 2 inch PVC because I'm growing lettuce right now.