I was able to keep mine within normal range by filling both pots. My hygrometer read in the 70-75% area with the humidity rising into the 80's once hatching commenced. When it got too high I simply opened the canopy to remove empty shells and dropped it back down to the 70's. Of course I was careful not to disturb the eggs unless a newly hatched chick had rolled a pipped egg onto the pip and then I carefully turned it so the pip was cleared of obstructions.
During the incubation phase I generally kept it in the 25-45% range without difficulty simply by adding a cc or two of water to one pot twice a day.
Has the OP calibrated their hygrometers? Mine were in a couple-three percentage points of one another so I considered that an acceptable range deviation.
Also, AmandaKyle, do you have the Mini Eco or the Advanced unit? If you have the Mini Eco, have you removed the plug where the turning motor would be located? If you have, replace it. I noticed that when my humidity went up during lock down, I had condensation form in the top of the empty cylinder.
If you are 100% certain that your hygrometer is accurate then I would just add a bit of sponge to the water well and watch your hygrometer. If you are in the high or mid 60's I wouldn't worry too much about it. Once the eggs start to pip and zip, the % will go up dramatically.
Good luck with your hatch. I really like my
Brinsea Mini Eco. It held the temp at a steady 100 degrees during incubation, and recovered temp and humidity rapidly when I turned the eggs. I was worried at first about the .5% temp deviation but had a 100% hatch rate with the 11 bantam eggs I put in it. I have come to realize that a broody hen has neither a thermometer or hygrometer built into her belly when she is sitting on eggs so both temp and humidity is going to fluctuate.
Let us know how it goes. We are here to help if needed.
