So, When I started my tank the pH was around 8.1 and held that way pretty consistently. I recently added my third fish and noticed today, three days later, my pH has dropped to 7.9. my KH is 12, so I don't want to add a buffer, what should I do to raise the pH back to the 8.1-8.2 range? check build thread for detailed info on setup, but right now I'm running a 75 gallon tank with canister filter and no skimmer yet