anderson LD601 20-Pack Dye Refill, Blue, 8-Ounce Anderson blue dye refill has a special concentrated dye that holds together underwater Help in leak locating dye is for the detection of leaks in light colored pools Works on plaster as well as vinyl and painted pools Plastic needle allows for precise dye placement without creating unwanted currents Available in 8-ounce and blue color; includes 20 refills per pack