Pond Boss Forums AQUATIC VEGETATION Controlling unwanted plants Brown Algae Problem?

I I'm just starting to stock my new pond with GS fry. The pond is 1-1/2 acres and was finished last fall.

Here's the problem; The pond developed what as near as I can tell is suspended Brown Algae and every time it rains it gets a little more dense. Visibility is down to about one foot. I'm reluctant to treat with CuS or equivalant becauce it will likeley kill the green algae as well as the brown and that is what the minnows are living on.

Anyone else have this problem? Ideas?

Bill Cody should be along shortly. He's an expert on algae. He identifies it for a living.

GSH fry are probably not directly eating the algae. First fry foods are primarily large protozoans, small rotifers and immature crustacea (nauplii). Some algae is probably incidently injested during first feeding experiences. Fry don't feed for very many days on the smaller zooplankton. They quickly grow in a few days to eat larger adult crustacean zooplankton.

However killing all the phytoplankton (brown algae) could compromise the phytoplanktonic portion of the food chain. Depending on the species of algae coloring the water brown, many of them are beneficial food organisms for zooplankton. Getting an identification of it first would be a real good idea. I do identify algae. It is definately a bloom of some sort. Numerous different species of algae can color the water brownish.

If you think you need to kill the "brown algae" you can treat just portions of the pond to thin it out. Liquid Copper based algacides would work to spray sections of the surface where most of the problem is probably occurring. If I was doing it I would use Green Clean liquid vs copper based algacides. Green clean is more environmentaly friendly and less toxic to the animal types. I would wait for a breeze and then spray the down wind area where most of the alage has gathered.

When it comes to ponds, what isn't Bill Cody an expert in?

I have made some phone calls to a local weed control contractor and he thinks the Algae bloom should only be about 3 to four feet deep from the surface, so I checked my discharge water which is piped up from the bottom of the pond. Seems at least there is no Algae at the 18' level. Cold down there too. The contractor also thought aeration would help? I thought Algae took in Oxygen? Wouldn't that make it worse?

Skinny dipping?

On second thought his pond is so isolated he may be an expert in that too.

Sorry Bill I couldn't resist.

Cecil, you'd know if anybody here did.

I'd swim in the buff if my swimming pond was behind a privacy fence. But since it isn't and Americans aren't very open minded about that kind of thing I won't. (One half of my family is from Germany and we don't have any hang ups about nudity).

I actually meant you'd know about Cody.

As I mentioned most of the problem is probably near the surface. The preponderance of algae can be at various depths from surface films to occupying the entire illuminated or photsynthetic light penetration zone (euphotic) depending on features of the various species and often affected by wind action.

""The contractor also thought aeration would help?"" It will most often indirectly help by spreading out the problem to all depths, so it won't look or appear as bad. Algae does use (respiration) AND make oxygen (photosynthesis). It only makes oxygen during day light when oxygen production is usually greater then the DO consumed, thus a net DO is added to the water. Algae continues to use DO during dark.

When mixed, to deeper depths algae may not thrive as well. It definately will not be as dense at the surface with distribution throughout the pond. The algae may not be at the deep dark levels long enough to hinder its development. Mixing has been noted to help suppress some species of bluegreen algae which you don't have. For you maybe? Mixing may be about your only non-chemical technique available.

If you choose chemical approach then having most of the algae at the surface is beneficial to make better contact with the chemial and the treatment more effective. Liquid spray is probably the best application for surface type films or concentrations. Maybe best to spot treat on down wind areas.

OK I'm starting to get the picture. Here is something else I noticed about the Algae.

The temperature at the bottom of my pond is 62 deg F. The Temp at the surface is 80 deg. It happens that my small detention pond 50'x 20' which precedes my main pond has a water temp of 70 deg F. The detention pond never has algae in it and gets water through an old underground 8" county drain. Is there a threshold temperature for Algae?