I've been using Healthy Mouth for over a year now and so far my vet says that all their teeth look really good. I took Riley to a specialty vet dentist who recommended it (along with brushing of course) after she pulled a few of Riley's teeth. I don't know if that was a side effect from her daily steroid use or what. I got the same size jug you got and even filling two bowls of water daily for four dogs, it still lasts forever.
The veterinary dentist also recommended some soft rawhide chews for dogs which also reduce prevent tartar,plaque and gingivitis and have the VOHC seal. They're sold by Tartar Shield and my dogs love them.