After running pastel ice white for about a year in a brand new loop, my coolant got a blue/green tint to it. When looking at the alphacool UT60 radiators, it looks like the copper is tarnishing on the inside. there are parts of the inside that still has the rosy copper color but the channels look like they've turned a gray/blue/green color. I'm thinking this is fairly normal but my coolant did pick up the blue/green color. I tested the pH was around the 6.5 to 7.5 ish range; nothing too far from ordinary.
Is it necessary and how should I clean out the radiators before filling it up with more pastel coolant for my next build? I've flushed the radiator with probably close 25 gallons tap water from the faucet and then followed up with a distilled water rinse. I'd imagine even if there were a pH imbalance, it'd be washed out.
The only components in the loop were a couple EK nickel water blocks, brass bitspower fittings, and full copper alphacool radiators.