# Daphnia - secret green water weapon!



## UnderwaterGuineaPig (May 29, 2014)

Hi everyone,

I just wanted to share how I've been using daphnia to clear green water in my Walstad tanks. I have several no-tech (except for a heater, now that it's getting colder here in the UK) Walstad tanks in our conservatory where they get direct sunlight for a few hours a day. When I first set them up, not surprisingly, they burst into glorious complete greeness! I couldn't even see an inch into the main tank. I left it for a while thinking it might sort itself out, but it persisted. I was beginning to miss my fish and plants, so I converted a breeding net into a daphnia cage (by covering it with a nylon sock, because the netting on the breeding net was not fine enough), added some daphnia (really cheap from my LFS) and waited. Within a couple of weeks they had multiplied to incredible numbers and after another week the tank was completely clear!!

An added bonus is that the daphnia themselves are just too cute! They're like underwater bumblebees


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## pandragon (Jul 10, 2014)

And now you have fish food as well! That is really cool. I need to start a daphnia culture some day, can't get any locally though. So far the only thing I have growing in my walstad tank (with a grow light since it is in a dark alcove) other than plants and snails is diatoms. I can't even grow algae to feed my quarantined otos, now that they cleared the tank of every diatom and won't eat wafers or veggies. 

I must be the only one who can't grow soft green algae for algaevores. I saw a speck of gsa once which got completely taken over by the brown stuff in days.


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