On my Canon iP5200 falls after several Refills always the color magenta completely. Then I fill the cartridge with ink to a half and the other half with Düsenfit. After about 3 intensive cleanings on the Printer Maintenance Tool this worked well again. In stubborn cases, I put the print head for 5 minutes in the with Düsenfit filled, enclosed shallow dish. Then I still admit each refill always 2 drops Düsenfit in the cartridge. Only when the printhead was printed too long empty, then burn through the heating elements of the print head, as they have no cooling by more ink. Even the motherboard can be damaged. When a defective printhead helps no more cleaning.
I have already ordered my Düsenfit often and am very happy with it.