I just had a batch hatch in my LG and I only added water twice in the eighteen day period, and then it sat at 30 percent humidity. I'm quite sure that I could have gone with out adding water on those first days , humidity was at 30 with out the water .I fill the channel's on the last three days and that spikes the humidity up to 70 to 80 percent .I have noticed that once they start to hatch that the humidity goes higher ?? .I open the lid as I please and it really hasn't had any bad effect on my hatching ? not to say that is correct , but it works for me .I just hatched 16 out of 24 and according to the seller that is a bit higher then her hatch rates , so I'm quite happy with the results .I think that as long as the incubator is in a stable area that the bit of humidity that might escape when the lid is lifted is not doing any damage at all .I keep mine in a spare befroom that is quite dry ( electric heat ) and I have no problems keeping the temp consistant , it normally drops by a few degrees when I open the lid ....but it's back up in no time when i close the top ................just what I'm seeing with my LG , might be different with others ??