what's the temp at egg level? that's what you need to pay attention to...
personally I detest the still airs. never had any luck with them at all. cheap fix, get a computer fan with the same hole spacing (measured in mm), think it's 120 mm but my memory's faulty. find a 6 or 9 volt cell phone charger. cut the end off, wire to the fan and plug 'er in. (don't tape or solder the wires until you're sure you have it right. if it's backwards the fan simply won't turn. switch wires and try again. then make sure when you put the fan in, that it's blowing UP not down. remove plugs from the bator and stabilize the temp again before adding eggs.
and personally, I DO NOT add water to the eggs until lockdown. and even then I still have wet hatches at times.
lately I've only been putting eggs in the hatcher once they've gone into draw down or internal pip. missed a couple that hatched in the incubator at less than 20% humidity too, without issues. but the later 'lockdown' seems to be improving my hatchability. go figure.