DCA
I had a older Dodge and the radiator was in bad shape, partly stopped up with hard water deposits. I installed a in-line water
filter that had DCA in it. The unit was installed in the heater hose. A by pass was installed to use year round. The truck heater worked for about 15 minutes and after replacing the filter with a new filter ( unit stopped up) the heater worked good again.
The radiator after a couple of years of use had no visible deposits in the radiator looking in the filler cap hole. I think that you can over charge with DCA, check with a test kit.
I am going to install one on the 95 dodge as it has some hard water deposits in it. I drained the radiator an flushed several times with water from water treatment. I should have replaced the antifreeze ever year and will do so from now out. The filter should help to keep the radiator clean.