This may work
I work with some ex-navy types. The first words out of thier mouths was "Bugjuice". Apparently if you make the normal recipe for Kool-Aid, but double the sugar, (times x for the amount you need) 100 gal use 10 gals of mix. Slosh it around, let it sit, slosh some more, it does the cleaning very well. Run it through all the plumbing. Don't drink it, just flush overboard. Safe and effective (so they say).