Thank you to those who have responded to my questions. I look forward to other responses. I emailed Dr. Falkinham (well known and respected microbiologist who lectures on NTMs) and asked him the questions about using distilled water to rinse the equipment, cleaning aerobika/nebulizer just once a day, and recommendations for shower head. The following is his response:
Dear Terry:

Here are a few answers.

Question 1. Yes, it is important to ensure that the water added to a nebulizer after disinfection is as sterile as possible. Rather than buying sterile water, simply boil the necessary volume of water on the stove, let it cool before adding it to the instrument. Use that water for rinsing and final filling. Rinsing with regular tap water will likely "inoculate" the nebulizer with NTM. Remember, regular drinking water has NTM. Also, distilled water is not sterile.

Question 2. If the instrument has been filled initially with sterile water it is probably all right to not clean/disinfect before the next use. However, remember, that it is possible to "inoculate" the nebulizer with your own sputum.

Question 3. Shower heads can be unscrewed and cleaned by scrubbing the inside as best you can and then submerging the shower head in Chlorox for 30 min. Alternatively, you can filter the water before it enters the shower head. Pall Medical makes 0.2 micrometer pore size filters and those prevent passage of NTM (we've confirmed). However, the 0.2 micrometer pore size filters clog easily, so we recommend adding a 5 micrometer pore size filter before the water passes to the 0.2 micro meter filter. The Pall filters are expensive and good for 30 or 60 days, so if possible, I would simply scrub out a standard shower head and disinfect in Chlorix for 30 minutes monthly.

Further, some shower heads have a fine spray and generate a great deal of mist that stays in the air of the bathroom. That is not so good as the NTM are in the aerosol. Look around for a shower head with large holes that generates streams (usually 1-2 mm diameter holes). That will not generate the mist that can enter the farthest reaches of your lungs. Big drops are better.

Let me know if you have further questions.

Merry Christmas and Happy New Year,

Joe