Strong Magenta cast on Canon ip 6000D

I have had a Canon ip6000D printer for 5 years and it worked great at all (paper quality) profile settings. Alas, it sat around unused a while and one of the colors clogged. I was unable to clear the clog so I bought a OEM Canon print head. Popped it in with the old cartridges and every color worked perfectly. All bands are even and uniform. However, after a couple weeks when I first tried using the Photo Plus or Glossy settings (any thing except Plain Paper), the pictures comes out with a very very strong magenta color cast. The Plain paper profile setting always works, but all other settings comes out magenta colored (faces are almost burgundy in color). I tried using Photoshop, the Fax and Photo Viewer, Picasa and they all come out the same with the higher quality settings. If I put a picture into WORD, then print with Photo Plus, it is Magenta, with Plain Paper setting the picture is correct.
I am using the same paper, same ink, same software settings I have always used. I see in the forums that this appears to be a very common problem. But I have not seen a reliable solution (other than to buy a new printer).
Some forum responses say the picture is having the printing profile applied twice so it comes out magenta. How do you turn one off?
Some say it is an absence of Cyan. But my cleaning and test print shows that all colors are printing very evenly.
Some say it is the printer mother board.
Some say it is just a bad print head.

Has anyone seen a reliable solution or various steps to narrow the potential problems down? I see this complain as far back as 2003. Is this just a defective head? Are the print heads just that unreliable?

I had a situation like this just over 1 week ago. I found that I had accidentally switched the photo magenta and magenta cartridges when I had taken all cartridges out. Fixed it immediately. I love this printer and the way it works.

I fill my own cartridges, and it also happened to me another time when I accidentally filled the photo magenta with regular magenta ink. I was able to empty the cartridge, rinse it out with water, and refill with the photo magenta ink. Worked great!

Hope you get back in business! Naomi