OK, I have been thinking about ways to accomplish this without another powerhead, pump or other inline device...
With that, I thought of something that might work, and, eliminate the external chamber entirely, and not add any more powerheads/pumps.
I wonder how much pressure is exerted on the end cap on my spraybar and how fine a bubble I can get to occur inside the spray bar...
Hmmmm, might give it a shot over the weekend.