With the Flip Flop Box DS85 all you need is an additional reflector and bulb for each ballast in your system. If you have two rooms in flowering mode, you simply use 10 reflectors in each room. Piggyback trigger cable allows daisy chaining additional controllers. When lights go off in one room the Flip Flop Box 10-In 20-Out, will flip power to the other room. Run lights in several different staggered configurations. Your ballasts will run 24 hours a day. Works with magnetic core and digital ballasts. If you have older HydroFarm ballasts and or reflectors, you'll need either GROW-BAASP or GROW-BAASR (sold seperately).