So for the first 8 weeks, my tank's pH steadied at 6.5 at night up to 6.8 during the day. I added fish, and in the last 4 weeks the pH has shifted to 6.2 at night to 6.5 during the day. This shift was gradual over the course of a month so I'm not worried about anything suffering, but I -am- concerned if I should buffer it back to 6.5-6.8, or let the tank naturally steady itself at whatever pH it falls to (as long as there are no large swings). Any suggestions?? Thanks!