This is my favorite essential oil diffuser, because it has a large capacity, you can turn off the light completely, and it has lasted for over 5 years. If you need complete darkness at night, then this is the diffuser I would recommend. I run this at night on intermittent, so that I don’t get an overload of essential oils while I am sleeping. All diffusers need to be cleaned out periodically to extend their life. I recommend a solution of ethanol/water or vinegar/water. The alcohol or vinegar will help dissolve the essential oil residue.