Old-Biscuit wrote:
Leaving your grey valve open can allow solids to remain (food debris/grease even body oils/skin, soap/conditioner residues etc.) which can build up just like a poop pyramid.
I've thought about this a lot and you are undoubtably correct. The only thing is that I think it would take years for a poop pyramid to form in the gray tank.
The water to solid ratio is orders of magnitude greater in the gray tank than the black tank. Add to that, the hot soapy water from the dishwasher and hot soapy water from the washing machine plus the agitating that occurs whenever I drive with the tank valve closed and I'd say it could be 100 - 1,000 years before any noticeable residue accumulates at the bottom of my gray tank as a result of leaving the valve open. I don't think the coach or myself will last long enough to experience this.
I've never heard of a poop pyramid in the gray tank. I'd venture to guess that most other RVers haven't either. It would have to be an unusual set of circumstances to produce such an effect -- No screens on drains, not wiping down plates, stationary for years, no gray tank rinser, unusual solids being washed, etc.
I'd go even further to suggest that an accumulation of solids and residues is much more likely if you leave the tank valve closed. After all, any solids in solution are likely to settle given more time in the tank.
Unlike my toilet, there are screens on my drains and I wipe down my plates into the trash before washing them. This results in few, if any, heavy solids that won't rinse away,. The reality is that the vast majority of any solids are simply rinsed down the entire system every time I run the water or take a shower. The majority of what's left gets agitated away during driving.
