I don't know what you ...

I don't know what you consider a problem with algae, but i would caution you that if the algae is not removed from the pond, either before or after applying an algicide, the decaying algae will deplete oxygen in the pond, so aeration would be beneficial. Also, if the pond has little freshwater input, the waste from the fish could be causing your problem. Microbes in the pond will convert ammonia waste to nitrate, but evaporation from the pond will concentrate the wastes. Like with an aquarium, adding freshwater or better yet, exchanging a volume of the pond with fresh will prevent the nitrates from causing an algae bloom in the pond. If you can prevent the algae, you won't need algicide.