Pond Boss Forums AQUATIC VEGETATION Controlling unwanted plants Raking Muck

Hello - calling back and answering the page - Muck raking can indeed in many instances help it "go away". BUT raking can also have other impacts on the pond ecosystem. Disturbing anoxic sediments can resuspend or swirl dissolved reactive phosphours into the water column to fertilize various forms of plant growth (FA, periphytic, planktonic and rooted). Massive rakings over a short time frame of anoxic sediments in a small pond can produce large increases of hydrogen sulfide and cause some fish deaths.

Some have found that bacterial or microbial additions alone can speed the decay of accumulated organic bottom materials. Which bacterial additions work best is IMO a crap shoot. Just about everyone that sells bacterial additions will claim theirs is the BEST. Trial and error may be the best path. What my work good for one may not work as good in another apparently similar pond.

In most of my experiences raking bottom sediments does help or speed the rate that they decay or decompose. Some of the raking activities just displaces the sediments into deeper waters. Raking does infuse oxygenated water into the often anoxic sediments and then fast acting aerobic bacteria and invertebrates can start processing the newly oxygenated solid organics. Good aeration activities of the pond will also help decompose the solid organics. IMO, I would shut off the aerator while raking so as to not unduly circulate disturbed sediments H2S and other strong annoxic chemicals throught the pond. And I would not rake more than 25% of the shoreline at one time. Over raking will proportionally distrub more accumulated phosphorus from the sediments and possibly cause objectionable plant growth (FA?) - depending on numerous features or conditions. Once sediments have settled somewhat then one can restart the aerator. Others may disagree with that concept, but that is how I handle it in my ponds.

However, I have one local pond owner that is telling me that frequent raking in his pond does not cause reductions of organic sediment build up in his swimming beach area. I am puzzled as to why his situation is different that most. I may have to do some testing there this summer to find out more about his problem. I have some theories but no proof.

More questions?