I wouldn't worry about alkalinity just yet.
Just my experience here, but when pH is over 7.5, alkalinity seems to be acceptable in most cases.
Yes agree with first part but the cause and effect are reversed. Ponds with good alkalinity have stable pH in the 6.5 to 8 swing range - that is the buffering power of good alkalinity at work. See the chart - flatter line. It is the wide swings that cause stress and if extreme then death.
.gif)
