If your temp guage does not have numbers on it to indicate what the engine temperature is, then you can bet your bottom dollar that just about halfway on the guage is your engines normal operating temperature,,or about 200 hundred degrees.
Flushing the system at home means that you drained all of the old coolant out,filled the system with water and operated the engine,,you repeated this process until finally clear water drained from the system.
Then you refiiled the system with water and added some powder or liquid flush agent,ran the engine about a 1/2 hour to give the insides a good scrubbing, drained and refilled etc, etc. until clear water draind out,,,yada yada,,,does that about sum it up ?
Now you probally are aware that you should only put distilled water in to an automotive cooling system and only in an emergency should you ever add tap water. That is because tap water has minerals in it and those minerals will percolate out of the water and clog up the radiator and the heater core and sometimes no matter how good of a flush job you do the heater core will still be clogged up and the car will never get warm on a cold winter morning, right ?
Usually you can tell if one heater hose is warmer than the other if the heater core is clogged, although they usually start to go bad after 8-10 years or so,some will make it 15 years but that is very rare.