How big is your CUC anyway? You could do the three day lights out method, it will make the algae alot easier to pull out, but manual removal will be needed. Have you cleaned your skimmer lately? It may need a good cleaning. Also, have you sprayed down your rocks lately? Next time you do a big WC, you might want to sray down your rocks with a powerhead and get as much garbage suspended in the water column as possible. Then do your change and try to suck as much of that water out as possible.