Thin layer of smelling gunk on the surface – Aquatic Algae

Q. We have recently bought a property with two small dams. We have cleared out the duckweed, but now we are left with murky water and a thick layer of gunk that moves around on top, it smells a little bit. What’s the best way to get started with clearing things up?


Hi there. It is highly likely that the floating gunk is algae, especially if it smells a bit. The best way to confirm this is to scoop up a little bit and check if the gunk is leaf-like in appearance.

Usually, aquatic weeds and algae compete with each other for nutrients in water, and when one disappears the other tries to take its place.
To treat algae, we recommend an approved aquatic algaecide like our Coptrol. Coptrol is specially formulated for use in water, and is environmentally safer than other commercial algaecides.

Click here to see more about Coptrol

The Coptrol will get rid of the floating gunk but if the water is left as is, it is only a matter of time before the algae or aquatic weeds return.

Brown murky water, especially if it smells, is often high in nutrients and decaying organic matter. It may be worthwhile to conduct a water test for an idea of the nutrient levels.

To improve the murkiness, we recommend using a flocculant. A flocculant will cause any suspended organic matter to clump together and sink to the bottom, clearing the water. Using beneficial bacteria like our Muck Breaker will then help to digest this matter.

Click here to see more about our flocculants including Clear Dam.

Click here to see more about Muck Breaker. The best thing you can do for a dam in this state is to install an aeration fountain. An aeration fountain will increase the oxygen levels in the water, while also circulating the water to speed up the breakdown of nutrients and decaying organic matter. Aeration can also speed up the digestion of  muck by Muck Breaker.
The waves created by the fountain will also disturb any floating weeds and algae to slow down their spread.

Our range of fountains start with the Half HP Evolution fountain, that can aerate up to 2,050m2 of surface area. For larger dams, we also offer more fountain sizes like the 1HP and 2HP.

Click here to see more on our Aeration Fountains.

by Aquatic Technologies
If you have any questions regarding looking after your dam or pond and what products are the most suitable for your situation, please read through the helpful articles on our site or feel free to contact our friendly team who can help you maintain proper health in your water body year round.
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