You can watch the whole video where these fine people test 12 or so brands of toilet paper for their
dissolving abilities to determine if they are safe for RV's... or
And the winner is "Great Value-Septic Safe Toilet Paper"
This is way cheaper than the expensive camper specific brands and it apparently works even better.
RV toilet paper needs to dissolve easily to that it won't plug your tank. It's the design of the paper
that makes it dissolve. It's not so much the chemicals.