Filamentous algae or blanket weed
CAUSE: Long, stringy strands imported into the pond along with new plants.
• Rinse new plants with water before planting.
• Remove algae by hand, winding it around a pole, such as a rake handle.
• On a waterfall, turn off the flow and allow algae to dry for easier removal.
• Use pond dye products (blue or black) to colour the water and prevent sunlight from reaching algae (be cautious of using these in early spring, as dyes will also inhibit the growth of plants).
Lack of water clarity
• Algae (see above for solutions).
• Suspended sediment.
• Clean filter more often and/or add extra filtration.
• Include an area with many varieties of shallow-water and marginal plants when designing your pond. Place a number of plants in mesh, water plant containers, which will allow the pond water to flow through their roots, creating a natural filter. In a large pond, submerge a bale of barley straw (available at some garden centres) to act as a filter. For a small pond, stuff straw into a pantyhose leg, tie off and attach a weight to keep it submerged.
Malfunctioning waterfalls/fountains (loss of flow)
CAUSE: Pump operating inefficiently.
• Be sure the pump is the right size for the volume of water. Pumps must not only satisfy the needs of water features but also cope with sediment, says British Columbia author and nursery manager Mike Lascelle. “Raising the pump even 10 centimetres from the bottom of the pond so that it's not sitting in sludge will help.”
• Clean the pond if sediment has built up to more than 2.5 centimetres. (Read up on the proper techniques or consult a pond expert.)