Checking PH is a weekly if not daily chore for us pond owners. If you purchase the test strips they do not always match a color on the chart. If you use the narrow range liquid reagent kits you may show a blue color any time your PH is above 7.5. If using a broad range reagent test kit it seems to not match any color until you get close to the outer ranges.
So I finally purchased a digital PH meter. These thick pen sized electronic devices display a PH reading from 0-14 in 0.1 increments. They can be calibrated using powdered control solutions. I found that my pond has been fluctuating between 7.9 and 8.4 which is somewhat high but is within range for my fish. It also helps explain why the nitrifying bacteria are not removing nitrites as well as ammonia. They are taking longer to get established.
I purchased my meter on ebay for < $17 including shipping. There are more expensive models out there and some are shipped from China so shipping cost is higher. Local pond and aquarium shops do not seem to carry electronic PH meters at least here in the Atlanta area.
