GLO Effex UV Reactive Water Dye is a concentrated UV reactive water dye used to create dramatic water lighting effects for all occasions or projects. Can also be used in any water based medium also to make glow in the dark products such as school glues, water based epoxies, etc. Highly concentrated with a mix ratio of over 50 to 1 so a little can go a long way. Just add to water and illuminate with a UV blacklight and watch the glow.