Five Star Io Star Sanitizer is a low foaming iodophor (iodine based) sanitizer. Easy to use in a measurable squeeze bottle. Economical dilution ration, self-indicating, controls water hardness, effective against most mold and yeast. Use 1 tablespoon of Io Star Sanitizer per 5 gallons of cold water. Requires two minute contact time. Can cause staining. 16 oz bottle.