I swear by the koralia powerheads. A bit more cash by a few dollars but they have magnetic mounts.
I was running 2 750 gph
in my 55g along with the fluval canister return.
In my 125g reef I'm running 2 koralia 1400gph units with a return flow of about 1000gph.
In my cube I just run a koralia 425 and the return pump.
In my 125g FW
tank I even have a maxijet for some circulation.
As far as sand, I bought pool filter sand from my local home depot for $5 per 50lbs. I found the play snd to be too fine and sharp edged as I plan on having sand sifting fish.
Hope that helps, I'm a little late for this thread. LOL