I've dealt with blue-green algae twice now, and I don't know if this will work for you, but...
In the first tank that got it, it was in an isolated area of long stems, so I just manually removed it and did a blackout for a couple of days. The plants were fine without light for that period of time, nothing was lost except the algae-fied clippings, haha.
In the second tank that got it, it was everywhere! Luckily only on the top portions of the plants, so I just cut it all out, basically. The tank looked rather bare, but things will grow back. This time I blacked out for a full four days. Again, the plants were fine during that period, so I wouldn't worry too much about depriving your plants of light for a couple of days!
So far I haven't seen a recurrence of the stuff in either of the tanks that have been affected by BGA. With blackouts, you've gotta remember that people ship plants all the time and they survive, so do what you gotta do to get rid of the algae.
I hope that helped somewhat, I haven't had my coffee yet so may not be quite coherent enough to explain stuff. >.<