Howto evaluate capacity of antracity and zeolite Filters on hot lime

[ConsultUS]

I am visiting an old plant with no enginnering records . This plant has a hot lime softening process with several Hot lime softeners and several units of antracity and Zeolite filter.
I hope Somebody please tell how to evaluate the operating flow capacity,
For the softening vessels I had sometime ago a Thumb figure based on retention time.
For the Filters and Zeolite filters I had some time ago some data as GPM/SF surface of filter area.
Is there any engineering design book where I can find how to evaluate more precisly the capacity

 

[aspearin1]

I came across a page yesterday that may have some info.

http://www.gsaresources.com/water.htm

There's a button there for cation-exchange. It can give a relative adsorption capacity for different zeolites for various metals.