Ahh that makes perfect sense. I'm not too interested in my CO2 being part of the DECO so I think running the two reactors will be best for me.alot of people use the diffuser's but they have them under filter intakes to further disperse it to the water collum. I have the inlets from my cannisters above my diffuser to suck up the bubbles and get them well chopped up and in the water collum.
So their filters are doing the real work. not so much the diffuser. actually in this setup the diffusor is more deco then anything else since you could pipe the co2 directly into the intake of the filter without any diffusor and get pretty much the same effect.