Faulty Products
It's been well documented regarding the black QD fittings and the corrosion that occurs over a short period of time. I only wish I had checked the reviews prior to placing a £300 order for these fittings as after just a couple of months use I too notice this very issue. Koolance didn't want anything to do with me after reporting this to them despite the overwhelming evidence. I have never brought or used a Koolance product since. Recommended to avoid them and avoid their products altogether.
By J W.