I'll add, I concur with ZytheEKs, Stickg1, and Jimhans1 in that it definitely appears that you left traces of acidic solution that threw your pH off, which often will change the color of the pastel. Mayhem has put out numerous posts in the community and other media that have addressed this type of issue in the past. The turning of color, especially towards a brown color, is generally caused by an imbalanced pH...most often from the improper flushing of radiators. Personally, I have some Pastel running in a system for almost a year straight now (24/7 mining) and I have no color changing, separation, etc. It looks as it did the day I put it in.
To say Mayhem is ignoring you is a bit unfair as he posted a page or two back saying that he sent you follow up questions in a PM. Additionally, it is outside of business hours as others have pointed out. And to say none of us care....well, you have 2 pages of responses to try to help with very little acceptance or acknowledgement from you. Mind you, none of us are paid employees or have any legal affiliation or commitment with Mayhems...we are just a community of loyal users that love the products and try to help others who are interested or have any questions or issues around the products...and also to look at the awesome builds that get posted in here. Please do not take your frustrations out on us
For completeness I wanted to add some further things to try: Drain the fluid and inspect the color in a clear glass (wine glass) in good light (outside full daylight). If it is clean, then check your tubing. If it isn't, try running it through some coffee filters a few times and see if it cleans it up. Since it was probably a pH imbalance issue, I doubt that it will do much good, but it is your best bet at salvaging your fluid.
Mayhems is working on adding additional information to their product descriptions regarding pH sensitivity and light reactiveness for all of their products. While it is not there currently, it is coming soon. This is to help customers pick products up front and keep them informed on how to use their products. I cannot say that I have seen any other company is offering this type of information.