Monterey MARK-IT BLUE is a concentrated blue colorant designed to provide temporary highly visible evidence of spray application patterns. MARK-IT BLUE readily dissipates, is non-toxic and totally compatible with water soluble solutions. It is ideal for golf courses, parks, cemeteries, athletic fields, and any turf or grass areas — virtually anywhere where spray evidence is needed. MARK-IT BLUE will not permanently stain vegetation, soil or human skin and can be used with all types of equipment. Application Recommendations: 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. More or less may be used, depending on turf or weed color, height and local water conditions.