Introduction to Pond Water Quallity Testing

The health of your pond depends on good water quality. Testing the water is an important step in monitoring the condition of the pond and its inhabitants.

Over time, ponds can become contaminated with high chemical toxins, particularly if the ecosystem is newly established or newly changed or if you neglect to maintain your filters.

See the chart below to understand which by-products are produced in the normal cycling of your pond.

Nitrogen cycle in ponds

A high quality test kit will test for pH, ammonia, nitrite, and nitrate.

  • High pH will cause any ammonia in the pond to become toxic, even at low levels. Always test for pH and try to keep it at approximately 7 - or neutral.
  • Over time, many ponds which started out with a high pH will begin to drop precariously low. Below 5.5 is too low for bacteria to thrive, and the biological filter will be damaged.
  • Ammonia is the number 1 killer of pond fish. It is a by-product of decay and decomposition. Suddenly adding a heavy fish load or failing to remove built up sludge and debris can cause high ammonia.
  • Test frequently for ammonia - especially during the early days after pond start-up. Ammonia is the first stage of waste cycling and the first to cause damage.
  • Nitrite is also damaging to fish. If the pond survives the ammonia created by decomposing waste products and fish elimination, the ammonia will be turned into damaging nitrite.
  • Nitrite turns into nitrate, which fertilizes plants. Too much nitrate and too few plants can cause algae bloom.