I've heard Ray Scott talk about fertilizing ponds and could not relate. Here in the Midwest, we have so many nutrients we have to avoid them to keep the FA under control. That would be the last thing you would do is to put fertilizer directly into the pond.
As I said, I'm trying to understand and relate. My assumption is that the soil is lacking totally in nutrients and that no vegetation will grow without some help. The fertilizer is necessary to get some plant life in the pond. If this is truly the case, and there is not a continuous source of nutrients, stop adding fertilizer, and with time things should come back into balance. The algae will consume available nutrients through what is called uptake. You can remove the algae by mechanical means thus removing the nutrients, or allow it do die and settle to the bottom where it becomes part of the bottom sludge. Aeration is also great to help with sludge decomposition and needed to avoid a DO sage and fish kill.
Restoration back to your expectations may take some time. If it is totally out of whack, you could try Cutrine or Copper Sulfate. I would recommend being patient, however.
