George @ Uvonics: When a Tin bath goes muddy, whatever color of mud, and it can go from White to brown, it is usually Stannic Tin oxides, which are the result of (1.) atmospheric oxidation of the Stannous Tin, and/or (2.) oxidation caused by too small an anode area. The Stannic oxides will co-deposit with the Tin metal, and cause the deposit to be less bright, and degrade the quality of the deposit. Some of the plating brighteners cause the Stannic oxides to precipitate so finely that they are VERY difficult to filter, (do I have to tell you that these are the ones that co-deposit the worst??) and settling and decanting may be the only way to get rid of them. Suggest you try filtering, if already filtering, try finer filter. Consult with vendor, if you are not filtering currently, to determine if this will screw up brighteners. When plating with Fluoborate bath, this does not occur, as Fluoborates are not completely stable, and decompose slightly to Fluoride and borate, and the small amount of Fluoride present complexes with the Stannic oxides to form a soluble Stannic Fluoride complex, which is inert, and does not plate out. Rudy Sedlak RD Chemical Company RD Chemical supplies answers, as well as solutions.