A: Yes it can! Wrap the coil as far away from the water heater as you can so that the water has time to be treated before going into the water heater. The factory can provide you with double coil length if needed so you could wrap the hot and cold lines separately. The 3 Star has the power to drive dual coils in series. Contact the factory for more information.
A: Yes sir, Scalewatcher is great in tandem with conventional water softeners. What you will find over time, is that you will be saving on salt and your softener will actually work better! By keeping the head of the softener clear of scaling, you will regenerate less and therefore save on water use too. Install the coil before the softener to save on salts.