Duck Weed Algae Problem

[peter.webber]

Hi Guys,

I built a duck weed tank in January and for a while things were going ok. Then I noticed bubbled forming under the duckweed, and when I scooped one up I found this slimy hairy algae that is growing from the bottom of the tank upwards. I am pumping water from the fish tank and the water is returning directly to the fish tank. I know I could cover the tank to stop the light but that would kill the duckweed. Does anyone have any ideas on how to stop the algae?

[GaryD]

Hi Peter,

Is your duckweed tank being used as a sedimentation tank at the same time, by any chance?

If so, get used to vacuuming your tank bottom each week as you harvest the duckweed. It's probably a good idea to vacuum the bottom of the tank to get rid of as much of the algae as possible anyway.

As the duckweed breeds up it will form a dense mat which will inhibit the growth of the algae. Only ever harvest half the duckweed at any time.....so that a complete cover quickly forms.

Can you isolate the duckweed tank (so that you can clean it up) without interrupting the rest of the system?

Gary

[RS_]

Hi Peter,

once the duck weed covers the entire surface area of the tank, the algae will be in the shade, and most of it will die off..... my 4' x 4' x10" duckweed tray did this last year.... i feed some of the algae to the baby tilapia while it was growing real good...... then harvested duck weed every other day for them......

RS