Bad Propane or?

We're having trouble with our propane system. About 2 weeks ago our generator bogged down so I went out to take a look and it turns out it wasn't getting enough fuel (LP generator). I have an auxillary tank with it's own regulator that is plumbed into the system down stream of the dual tank regulator. I turned on the aux tank and all was well so I figured the dual tank regulator was bad. I have a new one and will be installing in tomorrow.

Since that time, in the last week we've had the propane burner for the water heater stop working and yesterday the generator would no longer start, now today the furnace is having a difficult time firing.

The first thing that comes to mind is bad propane, or maybe the regulator attached to the aux tank is now bad too (it's only about a month old).

Ideas?