I don`t know the answer, but there is a very good Facebook group dedicated to Adria Twins and somebody there will point you in the right direction. It is called `Adria Twin Camper Van Owners`. I would also check that it isn`t just the stopper at the bottom of the tank, if that is the answer, the Adria replacement is expensive but if you need to replace it get back and I will tell you a much cheaper option.
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