This stuff really is the bane of the Koi keeper life but there are things you can do to control it or elliminate it completely in many cases.
As you probably know, Blanket weed thrives when it has two essential things: Sunlight and Nitrates. To get rid of the weed completely would mean either starving it of light, or nitrates or both.
Trickle Filters: You could try installing a trickle filter somewhere in your system. A round bin 36" high and about 12" wide will do. Fill it up with Flocor then mount a tray (like a plant water tray for example) at the top with 4mm holes 1" apart in the base of the tray. Pond water running through the holes in the tray will trickle over the flocor and after a month or so, your blanket weed should dissapear.
Trickle filters need a supply of clean water so it should be one of the last, if not the last filter in the chain. They work better whilst the water is warm, i.e. 16oC or above.
The second solution is to roof over your pond so that you starve it of sunlight. This coupled with regular partial water changes will help control blanket weed.
Posted on Jun 7, 2004, 10:07 AM from IP address 213.122.88.67