OK cool. I have a 3d background with the plumbing hidden behind it. I split the canister return pipe into two, one empties near the top of the background and one near the bottom. It seems to have affected the flow rate too much though, so I think I'll try blocking off the bottom return first which should get the pressure back up out of the top one and stir things up more.
Failing that, I see there are even smaller wave makers you can get, like 1000 lph, so perhaps one of those would work ok?