low vertical height

First time sativa grower in a 8'x6'x5.5' room,using 600 hps,4 bulb t5 54 watt agromax bloom bulbs,mars hydro ts 1000,& mars hydro 600 and 65 watt cfl 2700k.Ocean forest,happy frog,perlite mix in 5 gal airpots,using dirty dozen nutes.I let them get too tall before stretch so put scrog net on top...