I run 24/7 without problems and pH barely budges day or night (dKH ~3). I run the same level of surface agitation 24/7, i.e.; nothing special at night, such as airstones (airstones are not the best way to ensure good gas exchange).
Rather than focusing on bps, focus on moving CO2 to a point based upon fish comfort, but very gradually. One of the better ways of targeting is to compare pH of degassed tank water (a sample that has been sitting out a few days) to fully gassed tank water. A difference of 1 point generally indicates 30ppm of CO2, which a common target. DC's are ok, but can be misleading and do need to be recharged every couple of weeks.