BRANDS TESTED: ZeroWater, PUR, Brita, Aquaphor, AquaTrue, Lifestraw, Survivor Filter Pro, Frizzlife, Sawyer, RV Filter, and a homemade filter. Filters tested for removing total dissolved solids, removing red food coloring, and removing iron. Several filters were cut open after the testing to compare the filter media. I purchased all of the filters and supplies used for testing the filters.