Lots of opinions on this, but you will want to error on the safe side on this one.  Here's a link to an article devoted to TP and black tanks. http://www.aboutrving.com/pdfs/ToiletPaper.pdf
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Jon & Chris Everton
1986 40' Dog House #86
0 hp 8V92 Allison HT740
Soon to be 500hp ISM with ZF 6 Speed
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