interesting results: I just finished testing my parameters, and the ph out of my tap is a strong 7.6, as my tank used to be. However when I remodeled a few weeks ago, I added a large piece of driftwood. From what I've read driftwood can lower ph, and when I tested my tank, sure enough, it read between 7.0 and 7.2 (it was hard to tell the difference in colors, but it was clearly lower than it used to be). My ammonia is 0, my nitrites 0, and my nitrates 5. The fish I've had have had time to adjust to the changing ph, but water changes are still going to cause a fluctuation. Is the difference considered drastic? Could this be killing my angels?