Pond Boss Forums GENERAL QUESTIONS Help Floating algae mats?

Hey all,
I'm looking for some help identifying and solving a pond issue that I have been dealing with over the past year or so.

Starting last summer, I began to get floating mats of greenish brown muck on the pond surface, which of course is very unsightly. I chalked it up to the heat and thought I was under treating the pond, leading to an algae bloom. This year has been the same, if not worse in terms of floating mats and I'm looking to see what they are, and how I can take care of them for good.

The pond is 1/4 acre, 12ft deep, clay lined and roughly 35 years old. There are no fish in the pond. The previous owner treated the water with granular Cutrine Plus (in warmer months) and aquashade. I have been doing the same with no issue whatsoever over the past 8 years, until recently.

Chara used to run pretty rampant throughout the pond and its edges, which is mainly what the cutrine plus was used for. Since the removal of most of the chara, the chunks of muck have been lifting up off of the bottom and floating to the top. I have been manually scooping it out whenever I get the chance but I'm hoping to correct the problem instead of always cleaning up after it.

I have tried raking the pond sides, switching to liquid cutrine, beneficial bacteria, heavier doses of aquashade, and I put an aerator in a couple days ago (ramping it up slowly).

Should I cut out the cutrine all together and let the chara regrow to soak up the nutrients and give some stability back to the pond floor?

This was the worst of it after it all washed up to the beach



I originally thought they were some sort of FA but now I'm worried that they might be benthic cyanobacteria by the way they are lifting up in chunks and float on the surface. Hopefully someone has dealt with this before and can point me in the right direction.

Thanks,
Eric

I would allow the Chara to grow back in areas that are away from the beach to utilize some of the nutrients. You can still treat the beach area with Cutrine Plus Granules.

Would an alum treatment or some sort of binder help out in the meantime to reduce the nutrient load? Or is that something the aerator will take care of?

The aerator will not help with the nutrient load, it might mitigate some nutrients by allowing the bacteria at the bottom of the pond to start working, but to remove or bind up nutrients the algae needs to be removed or a binder needs to be applied. Honestly, to ensure that the binder is working, a water sample pre-application and post application should be done so that you have quantitative numbers for nutrient reduction.

You need to id the floating mats. FA does the same thing - float up in mats.

The mats hang from a stick but are not stringy. They also leave a little cloud of debris behind if they get jostled too much while scooping out. They do not have a foul or rotten odor so I'm hoping that is a good sign. I'll snag a sample and see if someone local can give me a definite answer on it.

See this for aid in plant id and mgt.

https://aquaplant.tamu.edu/