Pond keeping can be a very rewarding experience, but it does have its challenges. Whether you have a formal design Koi pool without plants or a more natural water garden pond, you are going to want to control the growth of nuisance algae. These two different styles will require different strategies to win the battle against algae.
The normal sleek design of a formal style pond requires structured perimeters with or without water features, such as a waterfall. It is not difficult to see where sleek and algae just do not mix! We have several options to control some of the different types of algae. The unicellular floating algae responsible for the “green water” effect can be control with chemical and mechanical methods. We can eliminate the free floating algae with the use of a UV Sterilizer/Clarifier if we select the proper size for the volume of the pond and use a water pump with the appropriate flow rate. For ponds with little sunlight or ample shading, adding a color tint (Pond Shade) can also discourage and disguise the effect of this type of algae. The tint will also inhibit stringy hair algae, but might require other methods to eradicate. Adding Pond Blocks can help control algae in these ponds without plants. The Blocks are a slow release tablet that will usually last for 2 to 3 months. We can also use the dry chemical Green Clean or OxyLift products to scourer hair algae from the sides or rock work of a waterfall. We simply pour these crystals directly on the algae to oxidize it in a mass of bubbles. Liquid algae water treatments are also effective on smaller scale ponds.
These liquid treatments (Algae Stop, AlgaeFix) are also effective against all types of algae in the natural water garden pond and will not harm the growth of the display plants. The UV Sterilizer is still the best option to eliminate the green water. We can also place Barley Straw/Bales/Pellets near water movement or at the base of a waterfall to naturally fight the growth of string algae. The Barley Straw allows the development of micro-organisms to compete with the algae for the available food (nitrate and phosphate) and can be supplemented with a product like Microbial Algae Clean. There are treatments like Pond Phosphate Minus that can remove the excess phosphates and help starve out the algae. The more types of ornamental plants we have, the better they will help control algae. Lilies obviously can cover quite a bit of the surface and block sunlight for algae while providing shade for the fish. Using large plots of oxygenating type plants with their fast growth can also help eliminate the excess fish wastes that contribute to algae. If possible, adding a bog area or partitioning part of the pond to make a bog can really help control the algae by natural competition for the food. The plants in a bog, Cattails, Cana Lilies, Sweetflag and Taro, make a great visual focal point and eliminate waste at the same time.