You don't have to do aeration fast -- it will take place slowly if you do nothing but maintain a lower pH. So, go ahead and lower the pH. If you can, adjust the pool returns to 'riffle' the water.

Worry about getting the chlorine up, and killing the algae. If it's still green with 5 gallon doses in the PM, go to 10 gallon doses! You'll spend less, killing it quickly than by slowly beating it to death.