Dry as a bone,…again

I was losing ALOT of water flowing out the vent tube and filler pipe while traveling; especially doing a sharp turn at speed and could watch it spilling out the side (some folks thought I was losing gas). To fix this, I put a turn-off valve in the line for the vent tube (used a on/off valve for lawn mower gas line). Also, I shove a piece of old towel into the filler pipe and cap the filler tube while traveling. I used to lose 1/2 my 40 gallons of water during a trip and now, not one drop! I've spent 7 days on the beach dry camping and still had water. Traveling uses a lot of wasted water right out the side of the RV.