With Caribsea Sea Pure you can stop wondering if your salt mix lives up to real saltwater. Stop worrying about harmful impurities in your tap water. Sea-Pure is real seawater and contains all the major and minor trace elements found in natural seawater in correct proportions and at the proper pH. No potential harmful pathogens. No nitrates or phosphates, no harmful organics, No artificial perservatives or chemicals. Sea-Pure is simply seawater as nature intended.Ideal use for small aquariums that require high quality water changes!