Pond Boss Forums AQUATIC VEGETATION Balance of plants in the environment Dark brown algae bloom?

We've been working hard to get the FA under control in our pond, and so far, it's been successful. Just a bit around the very edges. We also had aeration put in a month ago (4 disc diffusers on the bottom). It's been running 24/7, and will continue to do so. Pond is highly eutrophied and 40 years old. Pond has two inlets, both with sediment ponds and small damns. One inlet is fed via long deep grassy draw (lots of filtration). Other inlet is near gravel road, so has pipe feeding it from farmer's field across the road. Less filtration, but still has time to settle and then slowly feed into pond via two 6 inch pipes.
I am providing that background, prior to my question. Yesterday, I noticed the pond looking coffee colored brown. Visibility down to 6 inches or less. No smell. At one point, I could see the brown colored water where it met the more typical blue/green color of the pond, with a well demarcated border. Later in the day, full pond was coffee color. No evidence of fish stress. Caught one BCP, but not sure how she saw the jig.
Algae bloom? Trouble? Thoughts?

Hmmm... I'm no expert but could it be dying off FA? My pond turns from green to pond in the heat of the summer because, I "think", the cool water algae are dying off in the 85 deg. F water.

I wondered about that, but my water temp has only been in high 60s. But still a possibility. I guess as long as the fish aren't stressed, I'll just monitor and see...

Could it also be your diffusers on the bottom keeping this old pond "stirred up"? Can you get them off the bottom to see if that makes a difference?

I wondered about that too. I decided to let them go, as is. If the moving column of air and water stirs the bottom, I'm hoping it helps the native aerobic bacteria digest sludge and nutrients.

Algae blooms can range from bright green, to green brown, to brown, to blue green, or even red. Also I notice a brown tinge following a good algae bloom in my ponds, and I always attributed this to corresponding zooplankton bloom benefiting from the copious amounts of forage available to them. Regardless, since you are aerating this eliminates a lot of concern many of us would harbor regarding algae blooms/busts and corresponding DO sags/fish kill events. I would keep an eye on it but would rest easy.

That's what I was thinking and hoping as well. It was just such a dramatic color change, got me a little worried.

Could also be tannins if the runoff came from a field with dead crop residue. I get temporary tannin stains from wheat stubble or corn stubble runoff sometimes.

Also like TJ says, after a really good algae bloom sometimes a phytoplankton bloom to eat the algae.