I'm not a fan of any product that makes those claims. They're usually last resort type products that could cause issues elsewhere down the road in your cooling system. These are the key words that a lot of folks don't understand..."down the road"!
Make sure it's the heater core that is deffinitely where the smell of antifreeze/coolant is indeed coming from. The smell could be coming in from under the hood somewhere and the leak may be an easier fix than you might think...just sayin'!
Also, are you noticing any coolant loss from the radiator or overflow resivior? I know that the overflow resivior(way down low) is difficult to see on most Honda's and the level could also just be low due to the colder temperatures.
When the heater fan is "ON", keep in mind that you are pulling in some outside air from under the hood which could be bringing in some of that smell, where the leak may truly be...again, just sayin'!
Good luck
CB