To aerate when lowering alkalinity?

My fill water is high alk. Tests at 320. 3 times this year I've added acid and tried to lower it. First two times when I lowered the PH the alk dropped with it, from the lower 200s to 150. I had a suction side small air leak and was getting bubbling in my return flow that I thought would provide adequate aeration. Each time the PH rose, the alk rose along with it.

The 3rd time my PH dropped but the alk didn't really budge. I had my PH at 7.2, was aerating with return bubbling plus a bunch of normal pool activity to really stir things up. I notice after a dive or cannon ball, after the normal bubbling has stopped the surface of the pool looks like a glass of coke when you pour it and the foam goes away, carbon dioxide popping out of the pool. This is the desired result, right?

Is there a definite time frame during which the aeration must take place to get the alk to stay down?

The alk only goes down from the acid, not the aeration, right?

Pool water is crystal clear, but PH jumps back to 8ish only a few days after lowering it with acid. For some reason, the alk always goes back up with it. Am I doing something wrong?

Should I just keep dropping the PH and aerating and eventually the alk with lower and stay low?

Any help is greatly appreciated Oh, and I've not added any fill water since after the first time I added acid above.