What i am experiencing is different type of plants hv different timing to assorb the liquid fert. If you said dosing it right after the photoperiod. Then you gonna check on the Rotala species. The leaves will 'close' automatically after 6pm. Means...it is time to 'rest n sleep'. No matter you open the lighting at night or not. it still remaining closed.

What i read from some other article said...when the plants running the photosynthesis. It is not just need the lighting n co2. But some other source like fe, nitrate...etc.