I would agree. You need a powerhead and LR. I'd add about 15-20 lbs. and make sure there are hiding spots. The good thing about starting with damsels is that they are cheap and you know if fish will survive, just be ready to pull out all the LR to catch them.
I didn't use raw shrimp method, but I hear it works well from the people on this site. I used a bacterial addative with oxygen booster along with LR to get it started and my damsels seemed fine (not breathing heavy or signs of stress) when I put them in. I wanted to make sure my tank had cycled and it did. You can't see signs of this but you can test your water. I tested it and had LFS guy test it before buying damsels. They were about five bucks a piece and they took them back when I wanted to upgrade fish. I started with two clowns, always a good idea, they are hardy, friendly, and you have to be an idiot to kill them.
Best of luck