Black sludge

[CdnPond]

Help! We have black sludge on our water fall rocks. It is removable with a light brushing but it returns. What can we do to get rid of this problem? Thank you.

 

[brokensword]

probably algae; happens naturally. You can turn off your falls, spray it down with hydrogen peroxide, let it sit for half an hour, then brush/hose clean. It will happen again but this should slow it down as when you brush it off now, you're still leaving some algae behind, which helps with regrowth. Algae of this kind is a good thing for ponds and it should be on all your underwater surfaces, including where the water 'falls'! Nothing permanent, that I know of, to stop this as anything 'lethal' will also affect your fish and plants.

 

[CdnPond]

probably algae; happens naturally. You can turn off your falls, spray it down with hydrogen peroxide, let it sit for half an hour, then brush/hose clean. It will happen again but this should slow it down as when you brush it off now, you're still leaving some algae behind, which helps with regrowth. Algae of this kind is a good thing for ponds and it should be on all your underwater surfaces, including where the water 'falls'! Nothing permanent, that I know of, to stop this as anything 'lethal' will also affect your fish and plants.

Thank you. We will definitely give your suggestion a try.

 

[Lisak1]

It really is easier to just accept that it's a natural part of a pond. But like @brokensword said, you can clean them from time to time. Or you can turn off the waterfall on a hot sunny day and just bake it off. Nothing will be permanent though, so you'll have to decide how much effort you want to put into controlling it.