When to Test
Individual, one-time tests are only important if the test results indicate a toxic or dangerous condition, such as high ammonia, where corrective action has to be taken immediately. The greatest benefit of testing, however, is obtained when results are plotted on graph paper over a period of several testings, so that trends or directions can be noted early. By knowing the direction your pond's water quality is taking, you can take corrective action before the problem gets out of hand.

Normally, tests for ammonia, nitrite, nitrate, pH and temperature should be made once every week or two. Tests should be made more frequently during periods of change in the pond, such as spring warming, new filter installation, major pond cleaning or repair. At such times daily testings for certain items may be necessary, for example pH test during cement work and ammonia and nitrite tests for new filters. During stable periods such as mild summers, testing may be cut back to once every three weeks, and during periods of midwinter inactivity, testing can be eliminated.