1997 Chevy Blazer LOSING ANTI FREEZE

First thing I would check is is there coolent on the passenger floor under the floor mat just put your had on the floor up close under the dash and if it smells like coolent you have a leaking heater core if there isnt any thing there I would then almost lean right towards a bad water pump but the best way if you have access to a radiator pressure tester pump it up to 16lbs of pressure and then while it is pressurized check around the vehicle esp. Underneth look at the water pump and u will see a weep hole on it and coolent will run out also on the intake manifold where your thermostate is coolent also runs through there that is another trouble spot but that should get you wat you need