Whitey is right, they cannot be mixed.
Not all coolant mix is the same. Some use a component that causes a protective oxide layer to form on the insides of the parts, much like the copper oxide layer on the Statue of Liberty protects it from deterioration. Others use a silicate coating to protect the insides of your parts. Other additives may vary also. The determinant is what the insides of the engine is made of as well as the manufacturer’s design philosophy. You do not wnat to mix these, nor do you want to use the wrong one.
There is no reason to use anything other than what the manufacturer recommends for any fluid, and with some the risk can be great. Coolant additive is one of these.