You could use a lower pan and some kind of a deflector to keep the moving air off of the water or move the fan to one side with some kind of a partition to keep the air off the water.
Looking at your picture, when the water is full the fan is blowing across the top of your water and lowering the temp. You need to move the water or fan so that the water is only effected by the 100 degree temp. and not the fan.
Most of the older incubator instructions call for cooling the eggs, most of the new instructions just talk about temp, humidity and turning the eggs, is cooling necessary?
I purchased one dozen mail order eggs, they shipped 14, when received 3 were broken, candled the remaining 11 eggs, I...