I'm running two 150 on my 155. There mounted on the back wall of the tank in the corners of the overflow.
I'm running them on alternating gyre mode. At 2 min each cycle at max 40%, so there dead quiet.
This is how it works. So when I start them the gyre on the left will be at 40% in forward mode while the gyre on the right is at 10% in reverse mode (causing the pump to not make any water movement ) this cause me to get a counter clockwise current. This cycle lasts for 2 min then they switch. Where the gyre on the left goes to 10% in reverse mode and the gyre on the right goes to 40% in forward mode cause the tank to then get a clockwise current.
Fyi the rock work in my tank is about 3 to 4" away from the back wall so that the current can flow freely around the rock work. And the gyres r mounted vertically not horizontal.
But it does look very clean with no pumps sitting on the side walls of the glass.