Todd can tell you stocking numbers for your particular problem.
Depends on numbers of male tilapia /lb.
Thanks George. It's not really a problem. I could eliminate the filamentous algae with aquashade easily, but I thought I could see what the tilapia will do with extensive algae as a research idea for an article. The water in this pond, although nutrient rich, is gin clear btw. You can see the bottom at 12 feet. If it was 20 feet I could probably also see the bottom. The algae loves it for obvious reasons.
I've often said a guy up my way could possibly raise and market the tilapia for biological algae control and if he promoted it right could have a booming business. Maybe market both tilapia and grass carp. Lots of folks are frustrated using chemicals up here.
I will contact Todd at some point and get his recommendations. I really respect anything Todd says as I do you and others on this site.