What happens if I double the lines used to move gas?

I have alcohol fermenting in a milk jug to provide CO2 to my planted tank. Currently, I have one ';air stone.'; I plan to run an approx equal length tubing from a T-valve to a second air stone.



Currently, it looks like this: --------o

After (if you use your imagination), it will look like this: ---+=======8

The air stones after are not connected.



My question is how will the pressure change in the tubes from before and after? What are ways to address any issues to make the system more effecient from the stand point of a physicist?What happens if I double the lines used to move gas?
if what you are saying is you are running two air hoses of the same diameter from the same pressurized source, the pressure in each hose will be halved, compared to the single hose before.