I;m interested in what this "double barrel" action is about. Currently running two UC systems on a flip-box, same room but split down the middle with two sheets of black-n-white. I couldn't figure out a good way to keep the systems on the same "loop" since the split rooms are long (about 9'x20' on each side).
My lack of a solution there resulted in the purchase of two chillers, two pumps, two air pumps, two continuous meters, two PH down dosers, etc... The flip box is sweet tho. Make sure you use an MLC for the lights and set it up with two timers. You need about 1 minute of "off" on your MLC so that after the MLC turns off (and the ballasts are off), the flip box relay kicks over, then the MLC comes back on 1 minute later. Theres something with digi ballasts where they need that off time. Not sure the exact specifics but it has to do with a lower hz needed to start the bulbs. So in other words, when the digi starts up, its firing at a lower hz to get the bulds started, then after a few minutes it ramps up to like 600 hz. So if the flip box flips over to the cold bulbs on the other side, they cant start at the 600 hz the ballasts are running at.
Other than the high initial costs of setup, the flip flop is great. The other key is to make sure both sides strart veg and flower at the same time. The reason is you won't have an easy way to get adequate light for vegging while your using all the ballasts on the flower side for 12 hr a day. If both sides are vegging at the same time, just set it up to flip every 12 hrs in veg but change the order of the hood connections around so that it's staggering on each side.
So with a 8 hood, 4 ballast setup, each side has 4 hoods in linear "chain". for the first 12 hours, hood 1 and 3 on side A are on while hoods 2 and 4 on side B are on. Second 12 hours is flipped to hoods 2 and 4 on side A and hoods 1 and 3 on side B. Note that with this setup, you are only vegging with 50% of your total wattage at any given time but you are doing it with half the ballasts and half the watts usage that you would need otherwise. Plus, I've found that this is ample for the task at hand.
BTW, the flip box i use is from Horti Control.
Lets see the double barrel stuff when you can.