I sometimes add a shot of oxygen on day one of fermentation, especially for higher ABV beers. I've been overworked and stressed and lost track of days and gave a shot of oxygen at the end of day 2. I even noticed that activity was slowing down. I don't know what I was thinking. And, I lost count of seconds and did more than I usually do, I'd guess I did 15 seconds or so at a medium bubbly rate. I drew a sample today with a dip tube and it states stale. Question: if I add more yeast, do you think it will help? Tomorrow will be day 5. It's not a cheap beer so I want to try to salvage it. Thanks.