I add DCA4 with the antifreeze and I test the PH of the coolant regularly with a Fleet Guard PH test kit and if the PH isn't within the specified range, I add additional DCA4, which is a buffered solution to the coolant to bring it within the required range. Other nice thing about DCA4 is even in a parent bore (dry liner) engine, keeping the PH within specified range means your cooling system and radiator don't get internally clogged.
My Kubota's both run conventional ethylene glycol (green) coolant but I'll add DCA4 to them to keep the PH within the required range. I only own one wet linered engine and that is the 3406 Cat diesel in my farm truck. I change the coolant in both my Kubota's every other year anyway.
DCA4 is available online or at most any truck dealership's parts counter. It's a Cummins part but is used in all heavy duty diesel engines.
The Fleet Gard PH test kit isn't a cheap date but is a requirement for me. You can also use a Brix Refractometer to ascertain the PH level if you want to go that route.
One thing you NEVER want to do is mix extended life coolant with conventional ethylene glycol as it will turn to goo inside the engine.