Product review (5 stars): Worked very well to keep calcium and lime buildup out
We've been running several different varieties of humidifiers in out home for years, and this is the first time I actually purchased and used a bacteriostat.  Now that we did, I'm sorry I never spent the extra money in the past.  We have very hard water and I've used vinegar in my water in the past to try to keep the calcium level and slime build up with that, but it never worked.  This Holmes Bacteriostat worked excellent.  When I took apart the unit to clean and store away, I was amazed how clean the unit was.  I plan to use it from now on.