Okay, so I've been through the whole coolant rainbow - dyes, opaque fluids, you name it. But I keep coming back to PrimoChill's Liquid Utopia like it's my toxic ex (but way less problematic). Here's why:

First off, this stuff is crazy cost-effective. A $1 gallon of distilled water + this tiny 15ml bottle = more coolant than those overpriced pre-mixed bottles. My wallet sings hallelujah every time.

Performance? Chef's kiss. Two months in and my loop looks like I just installed it yesterday. No weird algae parties happening in there. And unlike some other coolants I've tried (looking at you, smelly Water Wetter), this one doesn't have any odor at all.

Pro tip: Shake the bottle like you're mad at it before using. It'll foam up for a day or two but then settles into being invisible - which is actually what you want! The real magic happens when you shine LEDs through clear tubing - looks like liquid diamonds.

Only downside? The MSDS info is harder to find than my motivation on Monday mornings. But after seeing how clean my copper blocks stayed during teardown, I'm sold. Bye bye gunked up colored coolants!