If you are doing chicken eggs, lockdown is day 18. Lockdown consists of stopping the turning of the eggs, taking them out of the turning and laying them down if that is how you are hatching and upping the humidity, I'd recommend at least 65%. Unless you have problems with your temp and/or humidity I don't see a reason you need to duct tape the sides.
I would help, but I'm new to incubating as well. Good Luck.
I have heard of some people using cloths and sponges but I had a bad experience once and now I feel I need to control the humidity a little more. When I first go into lockdown, I do fill the channels with water but after that if I need more water I use a dropper and drop water in through a vent hole. Usually I don't need more water, the humidity stays at the desired range, only if for some reason I opened the incubator. I have three and that seems to work for me.
Yes, you don't have to lower the temp. Some people do tweak it down a degree at hatch but it's not something that has to be done. I leave my temp the same as the first 17 days.
Have you ever checked your hygrometer for accuracy? Id not then your hygrometer is probably reading lower than the humidity actually is. If they are that small, remove the water from the incubator and pat it dry and run it w/o water for 24 hours. After running dry a day, check the air cells. If they still seem too small run dry another 24 hours. That will put you at lockdown day and hopefully you can proceed to lockdown w/o any problem.
At lockdown I fill all my water wells plus an extra little dish I have under the grate. Then I wet a couple sponges and place these on top of the grate (mesh/screen). When I need to boost my humidity back up I just grab out a sponge, wet it and stick it back in. You can use cloths as long as they are clean. I aim for 75% humidiity at lockdown.
I have both vents open as well, but I keep mine open for the whole incubation. I would not duck tape it either. (But I'm a meddler and often opening so it would be pointless....lol)
