BFL13 wrote:
On ours the FW tank bulges down when full. It is because the potable water tank is made of a more flexible white plastic stuff than the more stiff dark coloured plastic used for the grey and black tanks.
Not had any issues with any water left in there when "empty" if there is any. Ours does not need any extra supports underneath. In fact a support would stop it from bulging down so where would it bulge instead or would it just not fill as much? Not a clue.
I'm sure the bulge was caused by the weight of the water in the tank. When I observed this bulge, the tank was only about 1/5th full, so there was very little water weight.
From what I remember, the tank was supported a bit better in the middle, and the left side had the feed line and drain plug on the bottom.
It would have made perfect sense if the bulge had been where the feed line and drain plug was, but it was on the opposite side.
Is there a chance that the builder goofed and installed the drain and feed line on the wrong side?