highlighter dropped in tank

[Reef Puffer]

So any one know how to stop my water from glowing. Already dida 40 percent water change. What else can I do? Maybe I should put the tops back on the tank and not leave the 2 year olds near the tank when I use the washroom... Doesn't seam to be bothering any corals or fish but WOW does it glow under actinic lighting!