This table that I posted earlier in the Pool Water Chemistry thread shows how "out of equilibrium" a pool is at varying TA and pH levels. You can see that there is nothing magic or special about a pH of 7.2 but that you get further out of equilibrium at the lower pH which means that there will be faster net outgassing rate ALL ELSE EQUAL (i.e. aeration, surface area, wind, etc.).

In fact, if it really took a pH of 7.2 to cause the outgassing, we wouldn't be seeing SWG pools with rising pH problems above that pH, but we do. Also, the aeration effect to make pH rise wouldn't work above 7.2, but it does.

Richard