Try not doing that, bet it's similar or better yield in same period of time from light schedule change, plus less stress on plant.
Depriving of light for that long has a large negative impact to overcome for a net gain.
Keep it simple. React to plant. Start tracking ppm of everything you give, if you haven't yet. Will make deducing problems simple in future. One of the great things about hydry - water res or coco - is that you control everything in that regard.