Yeah, Stan, I mulled hard over the two sizes, but the smaller one’s stats seemed adequate and it’s measurements meant it stood up nicely in the “partial” pass-through bay opening adjoining the water bay, likely a unique feature of the 36ft Montereys. I usually tuck it tight on the ground behind the street side living room slide so it’s less visible from the campground road and less subject to theft, but with effort it can sit inside the bay with hoses running to and from the water side... just a bit of a squeeze when the door closes on them. I put an 8inch plastic flower pot tray under it to catch any connection drips in there. The Dirt Devil vacuum box on the bay ceiling keeps the unit from falling over, so no bungees have been necessary.
I discovered much to my triumph that the little devil seems to last far longer than anticipated before requiring a recharge. So the larger unit would’ve held little benefit, at least for our frequency of use. In fact I don’t think in several years it’s yet to need a recharge, used in the RV at most sites and often for filling the tank, and for many washes at home of our vehicles. A full-timer might want the larger unit.
But we’re kinda getting away from the original question here re. the water closet calcium removal.
Joel