Hi Frank,
no idea what AcidMagic actually is but as far as Muriatic Acid goes, mixed with hydrogen peroxide, it's dynamite for etching. Do some searches here for both of them, I think you'll find several threads on it.
I bought some 35% hydrogen peroxide from a chemical supplier (tried 3%, nothing happened) and a cheap gallon of builders muriatic acid. Just add enough hydrogen peroxide to "activate" the muriatic acid and get it etching good. Previously I used ammonium persulphate, but won't go back after trying the above. My boards are etched in under 2 mins and are nice, but my mixture has probably an overkill of hydrogen peroxide added, it's bubbling and fizzing from the start. You can keep the mixture and just add a bit of hydrogen peroxide next time to reactivate it, providing the acid hasn't "worn out".
Do it outdoors though, due to the fumes. Also muriatic acid fumes make steel flash rust so don't have it near any metal you don't want going rusty.
Keep hydrogen peroxide in the fridge or even freezer I heard, wrapped in foil to block off light, and move it as little as possible. This helps it last a long time I was told by the chemical supplier.
Keith.