The table shows that at start-up, Dissolved Oxygen levels are 0.4mg/l at the bottom depth of 30 feet and just 0.2mg/l at 15 feet, so the deoxygenated zone extends at least 15 feet above the bottom.
After 10 weeks, not only have Dissolved Oxygen levels been raised to 5.9mg/l at the bottom, at the surface it has increased from 5.15mg/l at start-up to 9.6mg/l.
This verifies reoxygenation of the whole water column.