There are several types of algae – floating and suspended algae need to be controlled. The algae that sticks to the sides of your pond, as well as in the rocks underwater, is considered beneficial. It actually competes with the harmful algae for food. Undesirable algae can be controlled by:

Oxygen
Aerate your water with a pump.

Barley Straw Pellets
In ponds over 100 gal, barley straw pellets will deprive floating algae of nutrients. A simple, inexpensive way to effectively clean your water
within 2-3 weeks.

Aquascape Pond Products

Maintain for Ponds – Contains characteristics of Rapid Clear, Detox, Beneficial Bacteria and a phosphate binder like SAB. Use regularly to keep everything in check.

Clean for Ponds – Contains characteristics of Sludge and Filter Cleaner, Beneficial Bacteria and Rock and Fountain Cleaner. Use to work on the sludge at the bottom of the pond and any organic matter in the pond like fish waste, uneaten food and plant material (leaves, etc.).

Clear for Ponds – Contains characteristics of Pond and Debris Clarifier, SAB and Rapid Clear. Use for green water, string algae or any other algae that may be discolouring the water.
Protect for Ponds – All natural, contains tea tree oil and plant based biopolymers. Helps heal wounds and protects fish from stress. Use after cleanouts, water changes or any other occurrences that may stress fish.

Do not change out more than 25% of the pond water at a time. Resist the urge to do complete water changes; refreshing smaller volumes of water will greatly reduce undesirable algae.