I imagine you are confused by now :B
*Toilet has two seals. Floor flange seal (toilet/floor gasket) and a bowl seal (inside toilet bowl) Bowl seal needs a liquid in bowl to properly seal. Cold temps...pour enough RV anti-freeze into bowl to cover seal. (or olive oil). Check in a couple days to make sure it hasn't leaked out of bowl.
*Black tank.....should have some liquid in it (even cold weather) so any 'stuff' in tank stays wet and doesn't stick/build up. RV anti-freeze in cold weather
*Grey tank.....should have a little liquid in cold weather. Pour RV anti-freeze down sink drains (kitchen/bathroom) and down shower drain....enough to fill 'P' traps and overflow a bit to grey tank.
*Under kitchen & bathroom sinks (inside cabinet) will probably be a 'vent' This are 'air admittance valves' that are on a short stub pipe just after 'P' traps. They are for venting when draining grey tank (keep 'P' trap from being sucked dry). They can wear out and not close......stink for grey tank can come back inside RV thru them. Just screw onto stub pipe.......replacements at hardware store couple bucks each.
All waste tanks (black & grey) have vent pipes......they go from top of tank up thru walls of RV to roof and have vent caps on them to keep rain/debris out of vent pipes. The vent pipes can get plugged.....then tanks don't drain like they should and odors from tanks can come back inside RV-----if the normal/regular vapor barriers aren't working (toilet bowl seal/air admittance valves/'P' traps)
You can use baking soda in your tanks (toilet/sinks/shower)followed with a little white vinegar (home made drain cleaner).
You can use ANY toilet paper that is 'septic system' safe. You don;t need to use expensive thin cheap made expensive RV toilet paper.
Use what you use at home.
Enjoy your 'new' RV and have fun!
Don't over think/over analyze. IT's just an RV. Similar to you home just on wheels.
Is it time for your medication or mine?
2007 DODGE 3500 QC SRW 5.9L CTD In-Bed 'quiet gen'
2007 HitchHiker II 32.5 UKTG 2000W Xantex Inverter
US NAVY------USS Decatur DDG31