At this point it would really really help to have a FAS-DPD chlorine test.
Assuming that you raised the FC level to somewhere around 15 last night after sunset and the FC level this morning was 3-5, you lost around 10 overnight. If that is all correct, then you have a couple more days to go. Given that you are not losing all of your chlorine overnight it becomes more efficient to only add chlorine in the evenings. You can still add chlorine during the day, and that will speed things up a little, but you will use more total chlorine that way as most of the chlorine will now be lost to sunlight.
Assuming that you raised the FC level to somewhere around 15 last night after sunset and the FC level this morning was 3-5, you lost around 10 overnight. If that is all correct, then you have a couple more days to go. Given that you are not losing all of your chlorine overnight it becomes more efficient to only add chlorine in the evenings. You can still add chlorine during the day, and that will speed things up a little, but you will use more total chlorine that way as most of the chlorine will now be lost to sunlight.