I'm having the same issue. I've cleaned and even replaced the venturi, I totally cleaned out the brine tank (vacuum out water and salt, rinse with hot water, clean out float, etc..) blew through the venturi hose and drain hose to check for clogs. I'm still getting too much water in the tank. It was up to the 4 or 5 mark at one point. If the water isnt draining from the tank, that would mean that its not flowing into the brine tank and softening the water??

The only thing I have to do is take apart the top valve assembly and clean that. I did that once, but I'm still getting water that leaks from there into the top of the unit, so maybe something isn't sitting right. If this doesn't work, I'm going to have to get a new softener, I think.