"Specifically" how long toilet paper takes to dissolve in the black tank? Huuum. It would take one heck of a grant for me to find out. So long as you don't confuse the hand towel with tp should be alright then agan maybe RV mfgs should put bigger discharge pipes on the tanks. A nice big 8 inch discharge out of clear lexan. Nothing else to do turn on the light in the tank and watch the paper dissolve and other activities. Lose a fork or spoon or yer dentures down the toilet. Just reach in and retrieve them. We could have contest similar to the track. Everyone bring a precise wad of their preferred tp. Have the designated wife drop it in the toilet and count how long ti takes to dissolve. Longest dissolving loses and gets to clean the tank for the next round, sort of like dealing the deck. ltimate winne gets trophy of dark stained tp in four shades as determined by the women and their picture took for the forum. :)