After reviewing your order history, I see you purchased the set of refillable carts and 4oz ConeColor ink bottles in 6/2012, then another set of 110ml bottles in 9/2013.
About how often has this printer been used vs. how long does it sit unused?
What is the humidity in your printing environment?
Have you cleaned the printer's capping station, wiper blade, and bottom of the print head? If not, I recommend you clean your printer by following our instructions, here: http://www.inkjetmall.com/tech/content.php?133-Printer-Cleaning-and-Preventative-Maintenance
Have any parts ever been replaced in this printer? Dampers should be replaced every 1-3 years, and magenta and yellow are always the thickest inks (this is true with all pigment inks, including Epson), therefore are usually the first to show sighs of particle build up in the dampers- indicating the dampers or ink selector unit have to be replaced.
Please let me know, thanks~ Dana