Since you had installed an Aerator, the obvious answer is that your effluent filter is totally clogged up with sludge that was stirred up by the aerator. Remove your effluent filter from the exit side of your tank and clean it.
The aerator stirs up sludge in your tank and packs this sludge into your effluent filter. If your tank does not have an effluent filter, then you should install one.
I suggest moving your aerator into the D-Box where it will do the most good. An aerator should only be used in tanks designed for aeration. Typically a tank designed for aeration has multiple chambers and only the last chamber is aerated.
Since your lateral pipes are relatively free of packed up sludge as seen in my videos, then your best hope is Hydrogen Peroxide 30% and septic seep poured into your laterals from the D-Box, or from the exit pipe out of your tank. See photos in my on-line document: