If you are determined to use chemicals such as algaecides which I do sometimes there are a couple of ways to go. Without getting all technical on you, copper based and what I say in slang, salty bleach. A sodium peroxide blend. Pick your poison. With the right applications usually quick results but you have only addressed a symptom, not the root cause for the problem. Plus you increase the chances of a worse bloom sinking all of that dead material for a new bloom, and maybe crash your entire pond. Just thought I would add that disclaimer.
