As long as you have added more oxygen to the water column, it should be fine. A powerhead aimed up at the surface where it is actively rippling the water's surface provides excellent O2 exchange.
If you had all three ready to go this is what the dosing would look like for 10-14 days of recommended treatment. But I wouldn't wait for the Furan2; I'd start asap.
Day 1- all three
Day 2- furan-2
Day 3- 25% waterchange THEN all 3
Day 4- furan-2
Day 5- 25% waterchange THEN all 3
Day 6- furan-2
Day 7- 25% waterchange THEN all 3
Day 8- furan-2
Day 9- 25% waterchange THEN all 3
Day 10- furan-2
Day 11- 25% (or more) waterchange
If you need to go 14 days-
Day 11- 25% waterchange THEN all 3
Day 12- furan-2
Day 13- 25% waterchange THEN all 3
Day 14- furan-2
Day 15- 25% (or more) waterchange