Pond Boss Forums GENERAL QUESTIONS Help Very old pond. Duckweed, Sludge. The works.

This past weekend I went down to Bill Cody's for a windmill. I'm still in process of assembly (it is a nasty thing to assemble). Anyways, my pond is 1/2 acre. 10 ft deep (to the top of the sludge layer). There is decades of sludge built up on the bottom. The surface is about 25-30% covered with duckweed (Bill already explained why this is a bad sign). I know the aerater will help a little and can't afford to have the pond rebuilt or dug out. I have been thinking of using Sonar/Avast to get rid of the duckweed. This should also control the duckweed for a couple years (according to directions). Is this a wise move? By keeping the duckweed from growing, would this help by NOT adding to the the sludge? Any other thoughts and suggestions would be much appreciated.

I'm going to do a little guessing here, your pond does not have anywhere to overflow to perhaps? If you were able to flush out duckweed when waters are high that could thin it out... At its present coverage, duckweed is doing a useful job of creating shady areas for fish and critters to shelter under during hot weather...

Duckweed provides a useful food for many fish, possibly you could introduce a form of carp you like, they will relish a lot of duckweed and may well obliterate it with time...

At 10ft deep most of the area of the pond is too deep for most aquatic plant varieties, so duckweed has little competition for fertility in your pond... If say 1/3 area was well planted with water lilies (less invasive types) and say 1/3 area well planted with oxygenators, aquatic iris etc, you probably would not notice the duckweed thrive so much...

It might be an idea to pick a corner of your pond to create a deep 'sump' area, where you dredge surplus sediments every couple of years or so, take it off and use it as a source of fertility elsewhere.... try leaving the rest of the pond to become shallow enough to plant with true aquatics in the future so the pond becomes more diverse for range of water depth and useful as aquatic planting positions

Regards, Andy