powerheads for fowlr

My wife and I got into the hobby in January. We each have reef tanks, hers a Red Sea reefer 350 g2. Mine in an IM 10g in my home office. We are looking to do a large fowlr and from what I have pieced together, there are some differences. My main concern is getting everything I will need so...

I have a 75 gallon FOWLR tank. I live in Hawaii so our laws are strict about pretty much everything about having a marine aquarium. So I won't ever be able to have anything but live rock. Do I need powerheads in my fowlr tank? I have a HOB filter and a canister filter both have strong output...