DIY floating scrubber not growing

[isenhart]

If it were my setup, I'd do some more testing before I abandoned the scrubber. You could make a temporary scrubber in your sump. Put a cfl or something similar shining on or though the glass onto something in the sump. If that grows better algae, then it's probably your leds. If nothing grows in the sump then something else is preventing the algae from growing.

[SantaMonica]

Care to try some antibiotics? If you have some Chemiclean or similar, it might be worth trying out, to see if reducing the bacteria population might encourage the algae.