Pond Boss Forums AQUATIC VEGETATION Controlling unwanted plants Algae and Phosphates

Working to clean up a 1.9 acre neighborhood pond. This pond has fish, two fountains, plenty of runoff, and outflow to another pond above a certain level.

Used 90 lbs of Airmax EcoBoost gradually over the past month. Yesterday's phosphate test showed zero, finally.

About a week ago the algae had a growth spurt and there's a ring of it remaining around the whole pond. I'm starting to think it might necessary to go back to an algaecide contractor. Is there any chance that the EcoBoost or some other non-toxic product could kill the existing algae? Are there any alternatives?

I had to look this up - Airmax Ecoboost is supposed to bind free Phosphate without affecting pH.

What are the goals for the pond?

The first goal was to get the phosphate contamination under control to prevent algae growth.

Now I need to get rid of the new algae, or at least most of it.

Ideally both goals would be comaptible, but the budget depends on how often the algaecide contractor needs to visit.

Is the pond for any purpose other than look pretty?

Occasional fishing and rowing. Trying to get some native sedges and forbs established in the shallow edges. Not intended for drinking or swimming.

Fighting filamentous algae is a common topic on Pond Boss.

Here is a link to one of the best discussions. It does ramble some, but that means it also touches on a lot of related topics. Might be a good one to read considering all of the possible management issues for a neighborhood pond.

Algae Control

My understanding is that you want to kill the algae first, then bind the free phosphate to prevent new growth.

You can kill the algae yourself with a tank sprayer and a solution of Cutrine Plus or Aimax Algae Defense. If the algae is in a ring around the shoreline, then it should be easy to reach.

As with most plant control, the best time for preventative treatment (pond dye, systemic herbicide, phosphorous binder) is in the early spring before things are actively growing. During the growing season, you probably need a combination of killing and preventing. I am doing the same myself right now.

Just to add, the Cutrine Plus won't affect the plants in the pond, JUST the algae if applied according to the label. It's best to apply it before noon as the algae doesn't grow at night. If applied in the morning, the algae should be turning color by the evening (showing signs of dying).

The season started with plenty of phosphates and not much algae. So I think that depends on the situation.