Update 10/2023-02/2024: So the GPU died... some time ago. It was bound to happen.
First delay: there was the GPU supply meltdown during COVID and finally not having the financial horsepower to go big, I went home... and opted for a previous generation RX6700XT reference board. Plugged it in and P:UV lives again!

Decided to rebuild the cooling loop during my first ever maintenance cycle - ever. Yeah, I know you're supposed to flush every 6 months, but because the GPU was dead, P:UV sat idle... for a year and a half. Found some galvanic corrosion in a fitting on the distro from the CPU. Enough to cause me to disassemble everything. There was a film of some sort on everything the water touched. The coating on the Thermaltake fittings is delicate and scratches and flakes easily. Scraping the corrosion off of it was an effort.

Cleaning the distro plate turned into a project of its own. First, identified some crust-ees hanging around the o-rings, rather gunk-i-fied threads where the crusty fitting once lived, and cloudy film on the interior water passages. Disassembling the distro requires removing the 4 screws holding the water pump in place (3 of whom stripped and didn't survive. Located replacement screws for the water pump at Titan Rig... in sets of 3.) and 35 screws holding the two plates together (8 of whom are hidden behind the RGB cover/logo/beauty plate) The plate is held in with adhesive, requiring some heat and gentle prying. Then finally cleaning the o-rings and a decent scrub with a toothbrush on the acrylic.

Rebuilt the hard line tubing loop. This time with frosted PMMA acrylic tubing for better light diffusion from the RGB fittings. PMMA tubing is a different creature than PETG. It takes a bit more heat to become flexible and has a slightly longer working window. That doesn't mean it's easier. I did notice it would stand a reheat a bit easier to correct or reform bends than PETG. But too much working or heat caused the same bubble issues. The frosted tubes also hid some tool marring and other marks, but would melt and turn clear if over heated or I had held too close to the heat gun. I found I could sand the surface to hide cosmetic issues caused by over heating the tubes.

Added another set of 6 TT RGB 16mm OD fittings.

Had a coolant blow out during non-powered testing caused by overstressing a fitting. PMMA is brittle. My measurements were slightly off and I added a bit more torque to the tube. Fortunately, the bend was on the lowest side of the loop so no coolant flowed down anything other than through the then-non running fans, the lower radiator and onto the workbench.

The Thermaltake fan controllers have ALWAYS been a problem. Not appearing in the TT control panel, and not running at speed. I will be replacing them with... something? in the coming months. Generally, I've found the Thermaltake products to be decent enough when it comes to the fittings, but a huge headache when it comes to fans and controller hardware.