High pH

Hi. I checked my pond's pH today and it was around 8.4. This is the
highest it's ever been. I had been under the impression that I was
supposed to keep the pH between 7 and 8, so I got scared and did a
partial water change. This was late this afternoon. Thought I'd wait
till the morning to recheck it, once things have equilibrated.

Ammonia and Nitrites were negative and the KH and GH were somewhere in
the 70-100 range I think (hafta go look it up; 5 and 6 drops with the
colorimetric tests).

I know I'm supposed to be watching for broad pH swings and could
probably use for the water to be a bit harder, but I was hesitant to
add anything that could contribute to the alkalinity of the water with
a pH of over 8.

I have been noticing spawning activity, and recently saw foam in the
waterfall.

Questions:

Is the sudden increase in pH maybe due to, um, "genetic material" from
spawning???

Is a pH of 8.4 okay? How high is it safe to allow the pH to go?

Thank you.

Joan
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