And for the last 3 days, you're not getting any sunlight into the tank from that window behind it, right? You can leave your lights off all day, but if sunlight is getting into the tank, the algae still have something to live on.
I know this post is 2.5 years old but i'm curious as to why the OP stopped updating. What ever happened to the green tank? Its like reading a whole book then realizing the last few chapters were missing.
I would have recommended cutting back to feeding once on Tuesday's and Thursdays till the issue passed as well.
That's what I do with my basement tanks, and then feed treats (massivore) on Friday nights when I'm drinking a "treat" as well (Gin and Tonic)...LOL.
Even on my upstairs "show" tanks I don't feed but once a day AT MOST(sometimes skip a day or so on them as well). We all REALLY DO spoil these fish....