with a 4 pipe system,one end of the grow (pipes) is capped and setting higher than the opposite end which is the drain end.run two 1/2 pvc feed lines connected with a T,one between each pair of pipes(parallel),install pairs of 1/4" tube-10/32 nipples in this 1/2" feed pipe.
they should line up with the 1/4" holes you drilled between every other grow hole in the 4 grow pipes,"on the top side" run short lengths of 1/4 vinyl(NOT CLEAR)tubing to 360 degree spray emitters poked in the holes between grow sites.
feed 24-30 emitters with 1100GPH or so, for a GOOD spray.
This will add more O2 to the root system than any amount of air pumps,and the growth rate will show this
you can not veg long with this system!
happy trails