OP,
For a 75 Gallon tank, these filters are ample enough in flow... If you really want to create a good detritus Lifter, You need Rolling and Twiting of the water column.
I use forward aiming of the outputs (which by the way, I use Lock-line Y's and jet outputs to turn my 1" FX5 outputs into to two 1/2" or 3/4" outputs) to roll that water column and then a High Flow powerhead of some sort to twist the Water Column. what ends up happening is that "stuff" get push toward the front of the tank and then back, then gets twirled around, Ultimately always passing everything by the intakes and getting sucked up.
But I breed so I have my powerheads on timers just after the lights go off at night for about an hour. This is usually good enough to lift and scoop the entire tank.
Just my 2 cents!
