That happens to mine. I try to shake the bag as much as I can during regeneration. If it looks really brown at first, I give it a good shake and bleach for another day. The ideal would be to tumble it in a reactor type setup, but I am not that sophisticated.
I use sodium thiosulfate to dechlorinate it afterward, and repeat the shaking and extra soak as I don't trust my nose (poor sense of smell). It's cheap enough that I don't feel bad using more of it. I also run an airline into the final soak to oncrease circulation.