I do not recommend a second filter, due to expense, and the added hassle of more to clean. I use filters for filtering but powerheads for adding flow and I favor giving the flow small bumps, rather than one large kick which may be too strong in one place and still not reach the far end.
Koralia are great but I find the small, cheap powerheads that I get for near $7 off the auction fit me better. In a 75, I may tuck several into the decor to hide but do the small boosts that I want.
I want to keep the leaves shaking but not pulled out of the ground!
Chisel out a hole in a small chunk of wood and hide a powerhead to blow out the backside?