Randomed

This is what the whole loop looked like in better days.

The color of the material is what had me concerned about copper oxidation or corrossion. I should also mention, whatever it is, it was more evenly distributed around the inside of the tubing originally. In the first picture those clear spots in the tube are where I had pinched the line and the blue/green material coating the tube flaked off and bunched up at the radiator. When I built it, I flushed/shook the radiators with distilled water and then flushed the whole loop with distilled before filling it with XL8. Nothing else though. The tubing does have a slight twist coming off the CPU and the radiator in the background. It looks worse in the picture than it is, but I will probably replace them if I have enough extra tubing. Flow seems to be okay, but I am just eyeballing it. I have been using the HydroX Pump default in ICUE and it seems to be running around 2000 RPM most of the time. What RPM are you running at usually?

Background: 1 year old build with custom loop cooling using all Corsair Hydro X parts (Radiators, Pump, CPU block, tubing, clear XL8 coolant) and an EVGA 3080 Ultra Hydro Copper GPU. Issue: I noticed some buildup in the tubing coming off the CPU block and thought it may be bacterial overgrowth or plastic. After tearing it down for maintenance though, I am thinking it may be copper oxidation. In the CPU block and tubing, there is a thin and flakey blue/green film. The tubing itself also has brown discoloration in other parts of the loop that don’t have blue/green build-up. When I did my initial research, I thought this wouldn’t be an issue since all of the parts are either copper or nickel plated copper. XL8 also has an anti-corrosive in it. Other notes: I did have a small (but consistent) air pocket in the top of the CPU block due to its orientation. Should be fixed now after rotating the block. On the worst tubes, some of the paint on the compression fittings was starting to flake off and expose what looks like copper underneath. I replaced the worst tubing and I am currently flushing the system with distilled water and Primochill System Reboot. So, a few questions: What is this and why is it happening? What can I do now to prevent or minimize the damage?