You sound like you have a chemical past
Meaning you're facing the challenge of letting go and trusting the microbes will sort their pH to the acidity they need. Fun stuff!
Did you know that in a root ball, you will find the whole range of pH? Tiny pockets of pH6, pH 9, pH11, all over the place, varying according to whatever nutrients they're cycling in that moment, in that area.... it's amazing!
Ah OK, no air flow numbers there, but I found them here:
http://www.tetra-fish.com/Products/aquarium-air-pumps/whisper-air-pumps.aspx
So the airflow of your pump is "2.6 L/min ("T"-ed)" - I assume they mean "using both airstones" when they say T-ed, which you are.
Minimum airflow: 0.08 CFM = 2.26L/min
and you need that
for every gallon of water to get the minimum dissolved oxygen of 6ppm in there to keep the tea aerobic.
So divide your airflow of 2.6L/min by 4 gallons and you have an actual airflow of 0,65L/min per gallon.
Way below what you need.
Or do it the other way around:
- with an airflow of 2.6L/min you can aerate 1.15 gallons of tea effectively.
- to aerate 4 gallons you would need a pump that has an airflow of at least 9L/min (or 0.32 CFM).
To test whether this is indeed the problem, you could try making that amount of AACT (1.15 gallons) with accordingly reduced additions.
Actually, Tim Wilson formulated the amounts in % to make them easy to calculate: the compost should be around 2,38% of the water volume, the molasses/fish hydrolysate should be at ~0,5% of the mix.
So for 1.15 gallons that would be like half a cup of compost with 1.4 tablespoons of food.