It's just as effective with a pump . If you want to do it that way get an adjustable pump and read the algae scrubber basics thread in the DIY section . It will tell you how to figure the gph
and screen size. Still will need some support bracing to hold it up. You can use the top of the tank or PVC
to make the support I stumbled on a few pics of a standup pump design online.Also make sure you can get lights on both sides of the screen about 4-6 inches away. So if you have a 10by10 screen you need 2 10 inch reflectors with 2 3200 k
cfl ( I think you said that's the lighting you are planning) one on each side of course . Just take some time to look at your sump make sure you have the room .