8-16 drops of bleach per gallon of clear water. let it sit for 30 minutes.
If the water is cloudy, double the amount of bleach.
If it is cold, double the amount of bleach.
Always strain the water before filtering. It'll make your filter last longer.
Always filter before adding chemicals. You want to remove as much of the 'big' stuff before adding chemicals.
You can always refilter to remove taste.