The maximum I would do with the 6055 is a 120. Here is the drawback though, you have no flexibility to upgrade. If you buy 6000's and you are totally into SPS, as the SPS grow and acclimate to flow which is more the norm in nature and not what they have had in holding tanks, you can upgrade the 6000 to a 6100 and get the added flow without spending much more. With the 6055 you may need to add a 3rd pump down the road. The nice thing about the 6055 is the ability to aim the pumps.