Or buy colored tubing, UV if you want.
Dyes seperate and stick to stuff. Some just dissapear. They really like the teeny pins inside a CPU block.
Most watercoolers who do this stuff a lot use distilled water and a biocide. Colored tubing and LEDs for color if they want color.
Dyes usually cause issues more than not.http://www.xtremesystems.org/forums/showthread.php?p=3837299
Why we use distilled water. Or de-ionized in the UK because distilled ain’t available unless your rich.