Take the lid off & let the media tumble dry , sunlight /fan will speed it up .
The red hue ya see is dust or transfer of shell particals, it adheres easier to the carbon inside of cases.
Turn on the tumbler & watch the action of the media/cases as ya fill it ,it`ll slow as ya fill & too much will stop it , faster rolling of the media/cases means faster cleaning.
Here`s what I use from the pet stores .
