Product review (3 stars): Red needs water light keeps coming on.  But full.
Very disappointed.  Cleaned it out again never tipping it.  Only ever used distilled water.
Does its thing but then shuts down. Says needs water.  It's just under the full line.
Worked great for 7 months.
After unplugging and restarting several times it started working again.
My advice would to never empty it totally.  My husband said it probably took time to prime again since there may have been air in the tube.