Just to echo what others have said, make sure that you're not using a "rapid" fix. For VanDykes (which are similar to Kallitypes) I use 1 heaping tablespoon of hypo crystals to 1ltr/1qt distilled water.
For toning, I use an ammonium thiocyanate/gold choride toner before fixing. It keeps well and lasts quite a while in its stock form.
Also, if you're getting a lot of bleaching during the fix you may want to overprint a bit (in addition to using a more dilute fix).