What film? Some, particularly t-grain films, don't stain that much.

I use a water stop and an alkaline fix, which will maximize stain but from what I understand, a standard acid fix should still leave plenty of stain left.

Incidentally the returning-the-film-to-the-developer step has been depracated. I have not done this for years and I still get excellent stain. However, I don't use a presoak; I've never had a reason to do so.