How to test pond water | How to clean a pond | Water garden care tip: Gardening

Helping You Become a More Successful Gardener

Balanced water quality is essential to maintaining a healthy water garden. Balance is achieved by establishing proper plant ratios, maintaining the water level, controlling debris and other organic matter, and testing regularly for the optimal pH and telltale nutrient levels of the water.

Water quality may be difficult to judge when algae clouds your water feature with unwanted growth. A good crop of algae actually reveals that the water likely has excess nutrients, sunlight and oxygen. Channel that all into growing healthy aquatic plants instead.

Reagent test kits are used to test water quality for several telltale compounds that reveal the water’s quality. Test kits are available at garden centers, nurseries and aquarium stores.

Choose plants selectively, and control their growth on a regular basis. The correct ratio of aquatic plants to water feature area is key to achieving healthy water quality and an overall nurturing environment for plants, fish and other living parts of your water garden. Maintain the following ratio of plants for each 50 square feet of water surface area. Such a blend provides aesthetic and practical benefits, while keeping the aggressive varieties in check:

Surface floaters – 6
Submerged oxygenators – 15 bunches
Shallow-depth marginals – 3
Deep-depth marginals – 3
Deep-water submersibles – 1

Always keep your water feature filled to its correct depth, as well. When your pond water turns from clear to green, you’ve got algae thriving in nutrient-rich water and sunlight. This actually signals a healthy, fertile aquatic environment ready to support more desirable plant life – so balance your feature with a proper mix of plants. Once they’re in and start to grow, the algae will subside, and the water will turn to a rich amber.

Look for these common symptoms of water-quality distress and what they likely mean for your aquatic garden:

Red water – algae
Brown water – loose or stirred-up sediment
Black water – decayed leaves
Milky water – organic decay
Rainbow slick – presence of oil
Drooping plants – herbicide draining into water
Failure to thrive – improper pH or soil mix
Excess growth – excess nitrite in the water
Stunted growth – excess nitrite or ammonia in water

Use a reagent test kit to test your pond water regularly for its pH (the water’s acid-alkaline balance), as well as nitrate, nitrite and ammonia levels. Nitrite from plant decomposition converts by chlorophyll photosynthesis to nitrate, a stable form. Excess nitrite signals too much fertilizer in the water, a condition that causes algae to grow and quickly turn the water green. It’s also important to check ammonia levels in the water, because ammonia from fish and animal waste can stunt plants and kill fish. If you test your water and ammonia is detected, take immediate action to remove it from your pond.

That said, garden ponds are more likely to become too alkaline and build up excess nitrite than to contain ammonia. If your aquatic plants appear droopy or discolored, and the water in your feature is an unhealthy color, it’s time to remedy the situation. Before immediately resorting to chemicals or draining and cleaning the entire pond, take the steps shown in the following pictures and described in their captions. A simple water treatment may be all your aquatic garden needs to get back on track.

Testing Pond Water

Testing Pond Water - Step 1

Study your water feature. The color of its water and surface should be a clear, tinted amber – like a tea beverage. Plants should be vital, green and healthy. (Algae blooms and weakened plants denote excess nitrate in the water or a high pH.)

Testing Pond Water - Step 2

Using a pond water test kit, take samples of your water to test its acid-alkaline balance. (Test kits and electronic pH meters are available at garden centers or water garden supply stores.) Optimum pH levels are 6.5-7.5 on a scale of 14.

Testing Pond Water - Step 3

Test your pond water’s nitrate load and nitrite levels, using reagent test strips or liquid test kits. The relative balance reveals the amount of the feature’s water-borne nutrients.

Testing Pond Water - Step 4

Test the water’s ammonia content, which should be zero. If ammonia is present due to plant or animal waste, exchange 10-20 percent of the feature’s water every 3-5 days until the water tests negative.

Testing Pond Water - Step 5

Remove and wash the feature’s biologic filter media. Clean the skimmer of accumulated debris. Exchange 20 percent of the water. (It’s generally unnecessary to use a chlorine or chloramine neutrilizer for small water exchanges.) Retest the water after 24 hours.

Facts

Good water goes bad in water features primarily due to dead plant and animal matter. These, in turn, boost the amount of nutrients the water holds, prompting algae to grow and fill the water, scum the surface and clog the pump. Rarely, other conditions cause the water to become too alkaline or acidic, killing plants and animals. Healthy water in any water feature smells clean – never fishy or malodorous.

Tips

Make it regular practice to replace about 10-15 percent of your water feature’s water on a monthly basis. But don’t throw the old water away: Use it to irrigate plants in the rest of your garden – it’s a great tonic fertilizer with numerous aquatic enzymes!
Algae are simple plants that grow in colonies. A little algae in your water feature is inevitable, but too much leads to significant care issues. Control algae by planting surface-floating plants to reduce the amount of sunlight the feature’s water receives, as well as using anti-algae enzymes (typically available from water gardening specialty stores and online).

Next Steps

How to Clean a Water Garden
Even water gardens need a good wash. While pond equipment requires routine maintenance to keep it performing well, the entire pond needs to be drained and cleaned on occasion. Learn a few seasonal tips to maintaining a garden pond, as well as the steps to properly cleaning it.
Repairing Liner Leaks
A healthy water garden relies on strong liner. But even the thickest forms can suffer from puncture wounds or tears after a few years of service. Learn the steps to repairing minor liner leaks in your aquatic garden.
Fertilizing Aquatic Plants
Fertilizing aquatic plants requires precision both in choice of the fertilizer and its application. Learn the four times to consider fertilizing your aquatics, the signs that may indicate your plants need feeding and the easy steps to applying the necessary nutrients.

Articles

Plants

Plant Search

Inspirations

Projects

Problem Solvers

Gardening Guides

Testing and Treating Garden Pond Water