Negatives came out horribly... Where did it all go wrong?

[Worker 11811]

Or, you can use a pair of tweezers or tongs and hold one corner of the piece of film in the fixer for 30 seconds. Then dunk the whole piece in. Stop the clock when you can't tell the difference between the corner you dunked and the rest of the film. That is your clearing time. Double your clearing time and you have your magic number.