I added mine long before co2 comes on then watched the tank just in case they showed signs of distress, i was ready to use an airstone, water change, increased surface agitation and turn co2 down. You can put a drop checker in the tank for a few days and if it turns yellow or yellow/green then there is good chance theres too much co2 for fish.
I've read your various threads and think you should stop increasing your lighting until your livestock is added, maybe even reduce it a little, then if you do need to turn co2 down then your plants will suffer less and it should be easier to find the right balance.
I'm guessing but I think you might have too much co2 at the moment because my ph drop was 1.2 when i added mine but your KH is quite a bit higher than mine