This humidifier has a 2500ml take. I ran it overnight on the middle level (2) and it appears to have only used about 500ml, so should be good to run multiple nights or continuously for a day and a half or so. It also has a timer feature (up to 8 hours) but that is not required, if you want it to run continuously just don't select a time. 

The lights are blue/white toned and fairly peaceful, but I prefer a dark room at night so didn't like having them on. I read that you can turn it to level 1 and the lights will not be on, so I will try that tonight.

Setup was easy. I used filtered water and some non-iodized salt I had at home. Will need to buy more as this is not something I usually have on hand, but it seems pretty convenient. I haven't done research on how the salt helps with stuff, but any opportunity for cleaner air is a good one.