Allright I received my UV clear and blue dyes from mlwood safely without any accidents ^^. Cant test in the loop yet but I couldnt resist testing them a bit. Here are my results.

Testing 0,15l (150ml) of distilled water in a normal drinking glass.

0 drops of Mayhem's blue dye


1 drop of Mayhem's blue dye


2 drops of Mayhem's blue dye


3 drops of Mayhem's blue dye


If rougly counted how much it would take to make 1 litre of coolant with those colors.
1 litre of "1 drop" water = 6,5 drops
2 litre of "2 drops" water = 13 drops
3 litre of "3 drops" water = 19,5 drops

No matter how you think, that 19,5 drops would seem a bit extreme since the instructions on the website say "max 5 drops per litre". Mlwood, is the blue really just that light or is there something funny with my test?

Tbh, the colors with 2 and 3 drops are around the area what I'd like my liquid to look like but both have over 2x the amount of dye your instructions suggest.