Spray solution blue colorant that indicates where you have applied a chemical spray. Works great with Roundup® or Remuda® and other herbicides as well as fertilizers and insecticides. Avoid skips and overlapping. Washes off without staining, is non-toxic and dissipates with sunlight. Mark-it blue should be added to the spray tank when it is approximately half full. use 1 Fl. Oz. of mark-it blue per gallon of spray.Shows where you have sprayed.Mark-it blue will not permanently stain vegetation or soil and can be used with all types of equipment.Works great with Roundup or Remuda and other herbicides as well as fertilizers and insecticides.Avoid skips and overlapping, Washes off without staining, is non-toxic and dissipates with sunlight.