Once again, thank you Bill for the very descriptive advice and answers. What would we do without you!

Just for the record, I spot treated only the areas that had FA. Next day it has had some noticeable effect. Any recommendations on how long it stays active in the water? Currently, pond has no water leaving due to the drought, but it does have water coming in.

Am I understanding this correctly?: The Phyco doesn't stay active for long. A heavy dose is/may be created at one application and doesn't build up from many over a period of time.