I don't see the purpose in putting a Color Catcher in with the 20 minute Retayne treatment. Are you mixing colors when you Retayne? Retayne sets the dyes, and I see some discolor in the water, but I only Retayne like colors together. After the treatment, which includes a rinse, you can check to see if the water runs clear.
I do like Retayne, but I always check after the process to make sure there is no more bleeding.