First, why do you think you have a poop pile? It gets a lot of discussion on the internet, but isn't really all that common and not the cause for every waste water problem. Please tell us more about the symptoms.
If a poop pile has developed, odds are it has become too solid to be dissolved with simple chemicals or detergents. It's worth a try, but chances of an easy success are low. High pressure water jet or a physical scraping may be needed. You can try softening & dissolving it with a concentrated solution of a detergent or a septic system treatment such as Roebic K47 or K57. It will almost surely take multiple cycles of soaking/softening (1-2 days at a time) and dumping.
You can put more of the Happy Camper Deodorizer in each tankful if you want, but it's a waste of money. It won't hurt anything except your wallet.