I started a new 75 gal cichlid tank and running a Cascade 1000 ggod too 100 gal. and a 4" air stone for added surface aggitation, but I plan on keeping alot of fish to depress aggression. I'm feeling that I do not have sufficient flow thu the tank and was wonering if I should add a power HOB filter like Penguin 400, or if a power head would be better..? Both would provide added circulation and added surface aggitation. But what direction is recomended? The additional filter would also help with clean-up for these messy guys and harbor addition benificial bacteria.. I will upgrade the canister to a Rena XP3 when I can as well... 
-fab5
-fab5