I have a question about dog shampoo - it might be a silly one. Petedge.com has 1 gallon of dog shampoo for $19.99. It's called Pet Effects - Tropical Collection. Has anyone tried it? Anyhow, it says "gallon dilutes 16:1." What does that mean? Do you add water? Is that a good buy? Please help - I'm new to this puppy grooming. Right now Marley is using "Just Add Water" dog shampoo from Target, but I'd rather purchase something higher quality. Thanks!