Colour your swimming pool blue temporarily. Give your swimming pool water a stunning blue appearance in minutes with the Aqua Pro Water Changing Colour Blue. The Aqua Pro professional range is a temporary, non-toxic and non-corrosive dye that does not affect the chemistry of your water. This product is safe, non-staining, and won’t leave residue on swimmers. Two applications of the dye are suitable for a pool of 50 000 litres and will last approximately 2-3 days. To undo the colouring process, simply add a cup or two of granular chlorine into your pool water and the colour will dissolve, leaving your pool clean and sparkling again.