Thanks for saving me the math

I'm a bit hazy on the exact reaction my self. Certainly the Iron is the most important as that's what's photosensitive. Comparing formulas that use the NH4 it does seem to be mixed at about double concentration.

I've been speculating on what the other ions may do but when you get down to it I have NFI either. I think I will drop Dr Ware and email as you suggest if I get an answer I'll follow up here.