@kate2025 When you say "Other groups have suggested to remove the carbon filter on lifestraw products because "carbon filters are known to harbor bacteria growth..." would you mind telling us who this is, and whether they have the qualifications to make such a recommendation? There are a number of NTM/MAC/Bronchiectasis groups that take a general idea about something (eg bacteria in carbon water filters) and generalize it to all filters containing carbon.

There is a danger in not recognizing the difference between single-stage filtering through a carbon filter and dual-stage filtering through carbon first and a .1 or .2 micron filter second. The dual filter catches anything that might be released by the carbon filter in the second one.

We use a 2-stage filter at our kitchen tap to eliminate the need for boiling all of our water. It is used for drinking, cooking, washing nebulizer equipment, washing food and cleaning water bottles.

To all - as for the "white" or mineral residue, the only way I know to avoid it is to used distilled water for steaming/boiling equipment.