That is way to high for a Whites. WTFs like a humidity around 70%. At 90% you are making a environment that has a high probability for a respitory problems/infection. Try to get it to drop about 20% and you should be in good shape.

Also if you are using the cheap dial type humidity guage you may want to get a 2nd reading from a different device. The dial guages have a high tendency to give a bad read out.