Hi Jason:
The solution of ferric alum (ferric ammonium sulfate) tends to be cloudy,
you can filter it, but  have the idea this solution is only for
sensibilization  purposes (please excuse my horrible english), and will not
keep
well (not more than a week). Think you are trying to do a Gordon-Sweet
method,which is a double impregnation technique,so it demonstrates collagen
type I as well as reticulin(collagen type III).
I suggest you to make first a simple impregnation method like Wilder=B4s , it
is simple and introduces you to the study only of reticulin fibers.
Good luck,
Carlos Defeo
Montevideo,Uruguay