I used a test strip and my ph and Alkalinity are are very high. How can I lower them?

What was the reading ?

The ph is 8.4 and the alkalinity is 240 ppm

I wish I could get those readings from my pond.

You should be ok - keep monitoring.

Alkalinity of 200 is optimum and pH of 7.4 is the pH of fish blood and is the ideal # (average blood pH of 7.4 for fish as per SRAC). See -
https://srac.tamu.edu/serveFactSheet/112

PH changes over a 24 hour period.