Aqua-Glo: Is the most powerful glow-in-the-dark thin-set overlayment in the world. It features all the superior benefits of our patented, high-performance FlexCrete resurfacing system combined with our non-radioactive, patented photo-luminescent additive which was specifically formulated to provide the longest and brightest glow scientifically possible. Aqua-Glo only requires 15 minutes of natural light exposure to provide 12+ hours of aqua-colored glow for well over 20 years.