I wouldn't expect DO to ever exceed 100% (and by 100% that's 100% of air saturation or 21% oxygen of the total gases at sea level) except in extreme situations where you have a massive amount of photosynthesis. We're sparging in room air which will equilibrate with the tank pretty quickly in a skimmer based system. Even if you remove excess CO2 from animals exchanging via their gills in the tank though heavy off gassing, you won't drop below atmospheric ~0.25-3 mmHg (your blood is around 35-45 mmHg in comparison) unless you scrub CO2. So you'd either have to pipe in pure oxygen to reach hyperoxic conditions (which wouldn't affect pH as much as reducing CO2 due to the buffering capacity of the bicarbonate). Correct me if I'm wrong here of course!
The paper is claiming that higher pH is more important for light calcification while 100% DO is more important than pH for dark calcification. My guess is that during the day the zooxanthelle are creating excess oxygen inside the coral tissue, whereas at night, there's more oxygen in the water than coral tissue as internal photosynthesis stops, leaving them more sensitive to hypoxic conditions.
In short, keep the system well aerated, reduce ambient CO2, and keeping temperature lower may help as well because lower temperature water has higher solubility for gases.
What's interesting is that a reference from this paper claims:
"coral reef waters during daytime is always accompanied by hyperoxia"
They measure DO between 27% (1.67 mg/L) to 241% (14.19 mg/L) over a full day-night cycle on the coral reef.
Of course, our aquariums are not direct analogs to the ocean. Is the scale of photosynthesis in the ocean enough to create hyperoxic conditions, while in our home aquariums it is not?