I have the same one. The instructions say to use only one water bottle for the initial incubation, and two during lockdown.First....started a tad early as we just flipped to 21 days. Oh..I put only water in one bottle and made sure to level the whole incubator...what do ya kniw...the humidity dropped from 71% to 46% !!!??

But due to my environment, I use zero water bottles and just put a tablespoon of water twice a day. It is the only thing I cant stand because that stupid alarm goes off if it dips below 40% (which is where I like it). It was the only incubator that shipped to the islands for free- and I got it on sale from walmart.com.