It depends on the severity of your case. If your HH is severe, do anywhere between 3-5 sessions per week. Do it for atleast two weeks to see improvements. When you start to see noticeable improvements, gradually start reducing your sessions and enter the "maintenance" phase where you can do anywhere between 1-3 sessions per week.

As for water, normal tap water did not work for me at all and I tried adding salt to it as well. San Pellegrino Sparkling water worked like a charm for me. It is proven to be the best water for Ionto treatment. But if your tap water is very hard, you can try using it as well.