Ammonia and nitrites should be 0, nitrates do a water change at 20 - usually
not a problem if you have plenty of plants. pH should be 7.2 or higher.
Generally it is what it is, so long as it doesnt go acidic and it remains
STABLE. You will have some swings from dawn to dusk due to respiration but
readings at the same time of day should be very similar. The stability will
be maintained by your alkalinity (kH). This is a seperate test and should
be at least 80 ppm. "It always used to work" problems are frequently
because the pond has built up mulm and needs to be cleaned. Excessive algae
or heat can cause oxygen level problems.
HTH
Bill Brister

"Carolyn" wrote in message
...
Umm, exactly what should the pH, ammonia, and nitrite readings be? Never
tested before, never had problems before. I believe we are having
problems
now because we have had such an unstable summer?

Carolyn