The picture was before cleaning i should have made that more clear. i removed the elbow and upped the flow again with the elbow the flow would have spilled over the top of the box as the oulet of the scrubber is in the water and provides some backpressure.
I originally wanted the water to only be at about 1-2 inches at the bottom as air transmits the light better then the water but that is only proberly minimal. Seams to be growing alot better now i increased the flow.
I agree there is more then likly phosphate in the rocks at it came from a faily amateur amateur reefer with a FOWLR system still using a canister filter.
The display exploded with the scrubber once i put fish in but i started feeding more as well so went hand in hand i guess. i cleaned just about all of it off with only leaving a slight green film remaining (didnt take a picture sorry) but it has grow to about 5mm thick in a day and a bit but doing much better with the excess flow i gave and started to turn greenish again.
I have no doubt it will return to green shortly or after this screen. i may up the flow a little more and let the box be more full of water i guess it doesnt matter too much as long as it doesnt overflow.
I'l take some before and after cleaning the next screen.