High performance coolant?

What is the best coolant (performance/endurance) to use in a custom loop?

I built my first custom loop back in May 2021 using EKWB cryofuel mystic fog. I’ve changed the fluid once about 3 months in and gave it a good flush of distilled water before replacing with more of the same cryofuel fluid. Now with about 4 months on the fluid in there and I’m again noticing the temperature of the coolant is getting really high if I have a really long 7+ hr gaming session. I have to crank my fan speeds up on the long sessions to keep temperature reasonable and avoid crashing.

Can I replace with a higher performing fluid that will require less flushing and changing? I’m assuming that would mean using a clear fluid with no coloring or suspended opaque materials mixed in. But is there a specific brand or type of fluid that will work the best for me? And am I correct that using such a fluid will perform better for longer without draining, flushing, and scrubbing sediment off the blocks and pumps?

Bingo. Anything translucent/opaque coolant contains solid particles, which will get caught up in the loop over time.

I personally just stick with Cryofuel clear premix.


Okay so anything crystal clear is going to work a lot better for me over time? I am past the “honeymoon” phase of the build and I’m totally okay going with a plain mix for less maintence.

Throw another vote in there for Cryofuel premix - I’ve got an X99 system w/ solid black tubing that’s been filled with the clear premix for two years now and it’s never needed anything other than topped off.

For the dyed CryoFuel premix, I’ve had two different expereinces: in a system with hardline acrylic tubing, it did perfectly for over a year until that one got torn down, came out looking the same as it went in. In the predecessor to that system which had soft tubing, it dyed the crap out of the tubing and the loop looked like hell after about a month but otherwise ran fine, it was just ugly which kinda defeated the purpose.

TL;DR I’d just run clear premix, and if you want color then grab some colored tubing next time over dyed coolant. Just my thoughts, YMMV.


H20 + Silver in loop for antimicrobial function (1 gallon of distilled is cheap AF)

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while high performance, no corrosion inhibitors means it’s is not a good long-term on most systems. By the time you research what else to add, you might as well have just picked up a clear concentrate.

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Been running the two for years never had an issue you don’t need anything else to add

Great, if only they had an exact replica of your set up and wanted it to work no less than two years.

Copper is more resilient than aluminum, but both with eventually corrode. Tubing material and flow rates will affect it as well. But eventually it will all corrode, even with inhibitors (though inhibitors slow down the process significantly)

+1 on cryofuel (non opaque). I use it in my system and am ~ 2 years in and it looks perfect. That said, I’m using all glass tubing in the loop and all copper based components (no mixed metals, except nickel coatings on the copper).

And, yes distilled water with a biocide works fine in most cases, but for long term use, I want a corrosion inhibitor and a biocide. By the time you buy the biocide, corrosion inhibitors and distilled water (you did confirm that the biocide is compatible with the corrosion inhibitor right :face_with_raised_eyebrow: ), the $18 for the cryofuel isn’t that bad for a tested formula with a track record.

For me this is ~$36 every two years or so ( I need 2L of coolant). Given the cost of the waterblocks, rads, fittings, pumps and other ‘wet’ components in setup, I’ll gladly pay that to protect my $1000+ loop.