A couple of days ago someone posted that it isn't a good idea to mix Deca and Fina because you don't want to learn the hard way if you will "react badly" to it.

Now I've done some research and found that all of the profile sites I see only tend to tell you what goes together rather than what doesn't go together.

Can anybody tell me what the adverse effects of this mix are and since the guy said that you dont want to find out the hard way that you will have a bad reaction. I have to assume that some people don't have this reaction. In those people does this combination compliment each other well and why?

I realze that this is a long question but if one of the more experienced vets could try and attack all of the points here I would appreciate it greatly.