This year our pond has experienced the biggest infusoria plankton bloom we have ever experienced. I have pulled a few samples and it is plankton and not alga growth. At first I thought it was alga but under closer inspection it is plankton. When we added the water to a clear bottle then placed light to the side of the bottle in a dark garage all the plankton moved to the light.
It has its cycle with the air stations and the day light hours. We do have millions of baby minnows and they are all gorging on the bloom.
I will do my best to get a few pictures tonight. I am worried that this bloom is over kill this year. It has never been this big and at 5pm can cover 50% of the ponds surface area. When the air stations turn on at 7pm it spreads it out. I know this is a sign of a healthy pond but I have never seen anything quite like this.
First picture. Now at first I really thought it was an alga bloom. After bottling up some I was shocked to see they are all moving. Then when I placed my phones light to the side of the bottle they are moved to the light.