I think (and stand to be corrected here) that the job of finings in the keg is to attract proteins or yeast cells using postive & negative charges and drop them to the bottom. In order for this to happen with protein matter in needs to have been brought out of the wort, this I think is the job of the copper finings. I guess if it were possible to do that none of us would use copper finings :hmm:
Aux Finings will drop out protein matter
Issinglass Finings will drop out yeast
I can't remember which way around it is but one is +'ve and the other is -'ve so they should be added 48hrs apart or they cancel each other out.
Like I say, i'm no expert on this and stand to be corrected, this is just what i've been told/picked up :thumb: