I would not let it fall much lower than that.
Do you run a fan? If so do not run it at night, or only run it with the lights. That seems to help as the humidity will go up to 100% at night in most cases. You could also block more of the fan if you are using one.
Just today I have checked all my tanks, and they are a little dryer than normal. Due to it being winter and only 20% humidity in my house and not 40%. I like to keep my takes over 90%, but most say 80% and up is fine.
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Kyle
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