Depends what you put in the tank. I have two tunze 6095 controlled by a 7095 and a wavemaker for my 120. I have quit a bit of rock though and I do a mixed reef so the flow is needed. I think the 6055 would be ok with limited rock and softies for coral. If you want more rock and sps I would bump it up or even find a used wavemaker and I think that would be plenty with the 6055.