It matters when you took the O2 readings (time of day). First light will be lower than late afternoon. Bloom probably is from nutrients brought up from the lowest anoxic water getting to sunlight and O2. More plankton/plants means more of an O2 swing night to day.

Vegetation will grow a few feet past where you can see a secchi disk. If the tops of the vegetation can get sunlight, it will grow even if the bottom of the plants don't see sunlight. They might not grow there next year, depending on the water clarity.

Every little bit that you are doing will help long term. I'd like to see the O2 levels in the 9-10 range, but you will get there.
3/4 to 1 1/4 ac pond LMB, SMB, PS, BG, RES, CC, YP, Bardello BG, (RBT & Blue Tilapia - seasonal).