Surface multilayer formation provides great potential for the tuning and optimising surface wetting properties and applications such as lubrication, drug delivery. Normally surfactants form a single layer at water interface. Under certain conditions, surfactants may form multilayer. The addition of electrolyte especial higher valence counterions such as Aluminium have been shown to generate significant structure and promote adsorption. SDS is a common impurity in SLES and yet its interaction with Calcium or Aluminium in the presence of SLES to our knowledge has not been studied. Here we propose to investigate the impact of multivalent countions on the adsorption and assembly of SLES/SDS mixtures at the air water interface by neutron reflectivity.