Join Date: Apr 2006
Location: Green Mountains
A big cup (eg. quart yoghurt container) full of water and a toothbrush for first manual removal (swirl the toothbrush in the cup of water and scrape it off with your nail to dislodge the algae you get out of the tank from the toothbrush). Dump the water with it in your garden or compost heap.
Add many Amano shrimp.
And get your parameters spot on (i.e. lighting wattage and photoperiod, CO2, and ferts).
Be sure you are not over feeding (the fish that is).
My guess: Do all of the above, and I think in time it will resolve itself. The higher plants (if you have enough of them) will starve the algae. W/o balanced parameters there is a big chance of a reoccurence IMHO.