Strange build-up in 5 days old block

Question

Hi Bitspower Support

Do you know what this is?

https://imgur.com/a/2tTNHr2

Can guarantee it's not the fluid, it looked the same with just distilled water while leak testing. Flushed the loop over 5 times before adding coolant.

New block, this is the 5th day of use.

Answer 1

Dear anonymous,

It seems the water stain with dirty of the loop is stuck there. Because there is no O-ring around the copper or acrylic, so the water can be passed through. Which radiator and other water cooling parts you used?