I would do both. It's early enough in the season to get results and enjoy it. Knock it out this year and clean up the dead stuff. Then do it in the spring to keep it from forming. Make sure you continue to aerate, dye the pond, and attack sources of nutrients.

Bennie
LMB, HBG, YP, CC, FHM, located SE Michigan
1/3 acre 8-9' deep, aerated 24/7 1/4 hp rocking piston