Gary,
You can warm up the engine to operating temperature and you will probably see coolant in the surge tank. If not just add a little water (preferably distilled) until you see circulation, then top it off with full-strength coolant of the proper type.
Yes, Cat coolant needs SCA (what your calling DCA) maintained to the proper level if you are running ethylene glycol (green) coolant. However, this is not true if you are running Cat ELC (extended life coolant) (reddish) coolant.
Gerald