Pond Boss Forums AQUATIC VEGETATION Controlling unwanted plants Worst algae bloom ever

My understanding is that if what you're describing is blue-green algae, the stuff at the surface and mixed in the water column is dead already. Wouldn't think any treatment other than skimming would do any good at that point.

The bottom of my pond is covered with live blue-green algae year round which starts dying and letting go from the bottom starting in early summer and runs all warm weather long. The live stuff makes the entire visible areas of the bottom of the pond dark, olive green and when it lets go in patches you can suddenly see the lighter colored soil at the bottom of the pond showing through. It's been getting worse every year and this is the worst year for it. The pond was unusable for recreation almost all summer long. Heavy rains might break it up and send it down but in a day or 2 it'd be right back.

The odd thing this year was that the die off was preceded by some dense, bright green algae of some other sort piled up at the surface that the catfish were tearing into for a couple of weeks. Suddenly, within a 24hr period, the dead blue-green algae started appearing and, although there was still large amounts of the bright green algae, the catfish wouldn't touch it since it mixed in with the dead blue-green algae.

The science appears to suggest that blue-green algae grows on barren, fertile bottoms - which fits my situation to a T. The suggested solution seems to be to knock down the fertility as TGW1 did and get something else growing to shade it out. My pond is turbid but the blue-green algae seems to be the only thing that doesn't mind the low light levels. Alum appears to be my best bet to clarify the water and knock down the fertility at the same time. I don't know if this compares to your situation in any way.