5 pounds? in what form? pure that would probably dechlor a large lake!

Only works on Chlorine... will break the bonds of chloramine leaving
free ammonia.

With Chlorine it forms NaCl (salt), salt will cause ammonia to be
released from many of the binders used to hold it (like the Ammo-chips
sold for aquariums ... not zeolite what is that stuff really called?)

Anyway all this is to say...If present ammonia should be dealt with
and tested before and after use.