new saltwater

[Maverick00]

Hey guys im now doing 15 gal waterchanges in a rubbermaid roughneck. I started mixing the saltwater maybe 4 or 5 days ago and didnt have the time to change it out until today. Looking at it now it appears the roughneck is starting to get a coating on the inside of the container as well as on the pump and the pump cord. I can rub it off with my hands and looks sort of greyish. Should I do a water change as normal or is this "grey slime or coating" going to be an issue?