Differences between aluminum sulfate and aluminum hydroxide as a flocculant in water treatment?

Can aluminum sulfate and aluminum hydroxide be used interchangeably as a flocculant and have the same effectiveness when attempting to floc various cations and anions that are in the form of dissolved solids?

Or does the presence of the SO4^-2 ion vs. the OH^-1 ion have more floc capability because of its larger ionic charge??