Water parameters... can you give us numbers by chance on NH3, NO2, and NO3?
I run an emperor 400 on mine - I replace one of the pads aywhere from once every other week to once a month. It hasn't harmed my GSP's or any other coral.
Did your LFS tell you that? I'd read around here a good bit - LFS are normally out to make money, this board is not :yes: .
Welcome to the boards!!!