I use a Canon Pixma Pro 9500 mkII, and I've found that the printer's paper setting can sometimes apply more ink than the paper can absorb. Granted, this is from a period where I was deliberately messing with calibrations to see if I could discover interesting effects, but sometimes the printer applied way more ink than could even dry on the paper. Mostly from the darker tanks, for some reason. I'm sticking to Canon papers now, but still dialing in my settings. I've had good luck with HP papers (glossy 13x19in and 8.5x11in) in the past, even when using a generic "glossy" printer calibration.
I also had a batch of worthless off-brand ink for the printer that was truly terrible. I sent those back to the manufacturer with a couple borked test prints and a nastygram in the box. Didn't want or care about a refund, I just wanted that crud out of my life.