First and only time I used a dye was Mayhems. Not even 2 months and I started getting temp spikes. I took everything apart and the dye turned into a jell substance that clogged up my blocks and the pump's impeller. You don't want to know how the inside of the rad looked like.
I took me a whole day of scrubbing with a toothbrush, pots of hot water through the rad, pump and res. I had to replace all the tubing as well. I went back to distilled/PT Nuke and colored tubing. 15 years later and not one single issue with any of my watercooling gear. Hell since I built my current setup, I haven't taken apart my gear for general maintenace. Clear is a bell since day one.
I always advise against using dyes/colored fluids, but some people won't listen. I just sit back with a bag of popcorn and watch the chaos unfold when people use dyes/colored fluids gunk up the works.