Hmmm, I haven't been using different water. I don't have a pH tester, so I cannot tell you what it is. It has been a little warmer in the house lately, but I didn't think that it was that much. I noticed that my heated tank has been a little higher lately, however, the goldfish have survived bigger temp changes than that without any problem. I have been letting the water for the changes sit for a few days before I change it (where as I didn't before), but I didn't think that would have an adverse effect on it. I just don't know. They seem quite healthy otherwise; their appetite hasn't diminished in the least (they try to attack you every time you pass the tank) and I am doing extra good gravel vacuuming when I do water changes. My angels are fine and I use the same type of water for them as the goldfish.