Pond Problem Solving - Algae Control

Fish waste, uneaten food, storm water runoff and wind-borne debris will all combine to increase the nutrient level in your pond. The beneficial bacteria in your pond work to break down this waste and convert it into nutrients that plants thrive on, primarily nitrogen. Excess nutrients - more than can be consumed by your aquatic plants and beneficial bacteria - will typically result in the prolific growth of algae. Your ponds ecosystem depends heavily on oxygen for this process, which competes with the oxygen needs of your fish. Moving water from either a waterfall or fountain is required to keep your fish healthy and happy!

The guiding factor will always be for you to build your pond where it will bring you the most enjoyment, of course, but the location you choose will require you to think through other factors.

Location	Will your pond get direct sun, and if so for how long? Four to six hours are required for blooming plants such as water lilies, but each additional hour of direct sunlight will increase your pond's temperature - and the amount of photosynthesis that will occur. Longer exposure to direct sunlight will increase the probability that algae (like other plants) will grow prolifically. If your landscaping plans call for the use of trees and shrubs to provide shade to your pond, use care when planning. Not only can they increase your maintenance burden, since falling leaves and other debris will need to be removed from the pond, but some species are poisonous - and others may give you problems with their root systems. See the ponds and trees page at Pond Expert for more information!
Size	Although space constraints and your aesthetics will ultimately dictate your pond's design, size definitely matters. The larger (and deeper) your pond, the more stable it's water temperature will be, and the easier it will be to keep your pond's ecosystem balanced. For help estimating your pond's critical measurements, see our "pond calculations" page.
Aquatic plants	Depending on your pond's location (and who you talk to) you should plan to keep 40 to 70 percent of your pond's surface covered with floating and/or emergent plants, such as water lilies. The shade they provide helps regulate your water temperature - and photosynthesis. Depending on your pond's size, you'll need sufficient volume of oxygenating plants such as Anacharis. If you choose to use fewer plants for aesthetic reasons, you will need to use other methods to keep algae-growing nutrients in balance.
Fish	It's not an uncommon problem to over-estimate the size of your pond and over-stock it with fish, which will increase the nutrients available for plant growth. If production of these nutrients exceeds the ability of your aquatic plants to consume them, you can count on algae to fill the void. Again, you'll need to consider other methods to keep your pond's nutrient level in balance. As a general rule of thumb, plan on 1 inch of fish for each ten gallons of water.

As the old saying goes, an ounce of prevention is worth a pound of cure.....

Feed responsibly	Any uneaten food will eventually add nutrients to the nitrogen cycle as they break down, and add to your difficulty in balancing you pond's ecosystem. A good rule of thumb is to feed your fish no more food than they can eat in two to three minutes. In the spring and fall, when your water temperature is less than 60 degrees, feed your fish a low protein food like Ziegler's Pond Fancier to reduce the fish waste burden on your bacteria colony. Stop feeding your fish when the pond water falls below 50 degrees.
Remove debris	Empty your skimmer basket and rinse your bio filters on a regular schedule. Your schedule will vary based on a number of factors (location, season, etc.) but these are relatively simple tasks that don't take a lot of time. When rinsing your bio filters, use pond water only. Your filter media hosts your beneficial bacteria, and you don't want to damage the colony by using a garden hose!
Trim plants	Removing dead or yellowing leaves not only keeps your water garden looking its' best, it also keeps them from decomposing in your pond. Spending just a few minutes each week keeping your garden looking good will pay dividends by decreasing your maintenance burden!
Change water	Partial water changes of 15 to 20 percent every three or four weeks will remove dissolved nutrients and help you keep your pond's ecosystem balanced. If you use municipal water, find out if it's treated with chlorine or chloromine. Unlike chlorine, chloromine will not break down over time with aeration, and will require you to treat the water before you add it to your pond. We recommend using chlorine & heavy metal neutralizer, especially when chloramine is present. This is an excellent  reference article on treating your water for chloramine.
Remove solids	Mulm buildup on the bottom of your pond will need to be cleaned to keep your pond as clear as possible. Draining and cleaning your pond should be part of your spring and/or fall maintenance tasks, but as an alternative to draining, you can also use a pond vacuum periodically to greatly reduce the time spent on pond cleaning!
UV clarifiers	Ultraviolet (UV) lights will kill the free-floating algae that can turn your pond's water into "pea soup". And no, they will not harm your pond's beneficial bacteria!
Quick fixes	Especially during the cooler months in the early spring or late fall, when your plants and beneficial bacteria are not fully active, string algae may be a problem. Just be aware that string algae is removing nutrients until your plants are again fully established! While you can remove excess string algae manually, you may prefer to use an algaecide. We recommend Green Clean, which will not harm your fish or other aquatic life. And it is always a good idea to replenish your beneficial bacteria, especially in these seasonal transition periods!