This manual is for BCH Refillable cartridge with transparent casing 

Product link:

• PGI-250 CLI-251 with ARC Chip (RC-CN-250-5)
• PGI-250 CLI-251 with Gray Cartridge & ARC Chip (RC-CN-250-6)
• 5PCS Refillable Cartridge for CLI-8 PGI-5
• 7PCS Refillable Cartridge for CLI-8 PGI-5
• PG-220 CLI-221 with ARC Chip (RC-CN-220)

If you need to refill Canon's original cartridge (OEM), check out this article: https://support.bchtechnologies.com/hc/en-us/articles/200667459

Preparations

Before opening your refillable cartridge, please perform printer nozzle tests to ensure your printer is in good condition.  If your printer has produced a perfect result, please attach a copy of the nozzle check to your purchase receipt as this will validate your warranty. You can now start to install your refillable cartridge. 

If your printer has printed with missing lines or uneven coloring, please repeat head cleaning. If your second print is similar to the first, let your printer sit 2-3 hours then run another nozzle check.  If you still see broken lines, then do another head cleaning and let it sit 3-4 hours.  Sometimes it takes 3-4 head cleanings.  DO NOT run more than three head cleanings in a row without resting your printer for few hours.  If your printer still has broken lines, you more than likely have damaged printer heads, and you will need them replaced before successfully installing a refillable cartridge.

1. Install the silicone washer around ink intake.  PGI-5 CLI-8 PGI-220 CLI-221 PGI-225 CLI-226: Do not remove the back washer from Canon.  PGI-250/CLI-251 (Purchased Before 2/1/2017): Remove the black washer from Canon.  Lay a washer on the top of each black grommet around ink intake. PGI-250/CLI-251 (Purchased After 2/1/2017) We made improvements on the cartridge design and the cartridge no longer need washers.  The package will not come with washers either.  Please skip this step.
2. Tear off the yellow stickers from BCH cartridge.  There is an air vent beneath the yellow sticker.  Make sure the glue does not block the hole.
3. Remove the color refill plug and fill up the cartridge.
4. Insert the refill plug and use as a normal cartridge.

TO RESET INK LEVELS:

You cannot force the printer to reset ink levels.  You have to wait till the printer display an error “ink cartridge cannot be detected” (not just low ink warnings), and then open and close the printer lid.  The ink level will be full again.  This is because the reset process must be triggered by a printer error (a warning is not error so the low ink warning will not trigger the reset).  Once the reset is triggered, you need to let the printer think you changed to a new cartridge, so you open and close the lid.  If the reset fails, you can repeat the process and also power off the printer.