Part of the commitment you make when you decide to install a water feature is maintenance. In many respects, the smaller a water feature, the more maintenance it requires (per unit of size). Forget about relying totally on chemicals and an occasional cleaning. Water features aren’t pools, especially when you decide to include fish.
Filtration and aeration are very important with smaller features. You want a minimum depth of 3 feet with constant circulation and filtration. Waterfalls or circulation pumps should pump water through a properly sized sand media filter. The media in the filter should include two-thirds sand (12 to 16 mesh) and one-third activated charcoal. The filter will remove organic contaminants and keep the water clean. Waterfalls can increase oxygen content as well. If you don’t have a waterfall, install a bottom bubbler or injector-type of aerator to go along with the circulation system.
An alternative to a media filter is a biofilter, which is essentially a gravel bottom that acts as an intake through which the water circulates. Beneficial bacteria (aerobic) will become established in the gravel and keep the water both clean and fresh. At least two-thirds of the feature bottom should be covered with a foot of gravel over perforated drain lines that return the water to the pump. Use river rock or granite. Avoid limestone.
Some algae (filamentous) are actually preferable for fish. Consult fish suppliers or your fish stocker source for the right number and combination of fish to place in water features. Avoid overfeeding fish to avoid organic buildup.
Dyes can improve the appearance of shallow water features and slow the establishment of aquatic weeds. Dyes also do not hurt emerged water plants like waterlilies. Do not paint the bottom of water features a dark color that will absorb heat. Make them reflective to keep water cool. Avoid rough concrete surfaces in favor of smooth surfaces for the fish.
If you stock your water feature with fish, provide access for observers to enjoy watching the fish, such as bridges and decks. Visible enjoyment should be balanced with audible input, so include waterfalls and fountains. Lighting is very important in water features at night.
Like larger features, the safest bet is a natural balance among fish, beneficial microbes and nutrients. In the case of small water features, this weighs heavily on filtration and aeration. Chemicals can’t replace basic mechanical measures. But an occasional clarifier or dye might spruce up your water feature now and then. Depth and shade for at least part of the pond is helpful.
Water features provide a type of enjoyment that has lasted for millennia. They are now available to a greater number of people. Keep in mind the thinking of our Buddhist predecessors: pay attention to the now, and you will assure the success of the future.
Patrick Simmsgeiger, a second-generation expert on water management, owns Diversified Waterscapes, which has three locations in California. His company also manufactures water treatment products, from clarifiers to aquatic herbicides.