For what it is worth, most of today's RV builders DON'T use slosh in their
tanks. In the old days, some builders were having problems with slosh
coming loose. Imagine having to open up a tank to remove mis-applied slosh
(or risk clogging your fuel filter with the stuff when it flakes off). Some
builders who didn't slosh had a leak or two, but it was easier dealing with
the leaks than with slosh that wasn't staying attached...

In the end, if you do everything right, you don't need slosh. Beyond that,
if you slosh *properly* the slosh won't come loose. It comes down to
following proper fitting, cleaning, and prep procedures all the way through
the process - slosh or not.

KB