I can't help you with the refill but I can tell you a bit about the rest.
Firstly, forget BPS as 1. It's not a standard measurement due to everyone's bubble counters being (slightly, if not completely) different. And 2. The amount of CO2 you need isn't proportional to the volume of your aquarium. A 200L high tech tank will need a LOT more CO2 than a 200L low tech tank. What you need is a drop checker (and preferably a fishless aquarium) so you can slowly increase your CO2 and get the timing right. I like to start my CO2 about an hour before my lights come on and then turn it off half an hour before the lights go off. This stops the fish getting gassed overnight but also gives the plants a good head start when the lights come on.
And that answers the third question, an air stone shouldn't be needed at night but I find my fish need at least a little bit of surface movement to prevent them gasping.
Hope that helps