To much humidity?

[milk man]

I Have been having trouble keeping my humidity up in my Cali king and Honduran milk snake's tanks. So I put plastic wrap over the screen top to keep the humidity up, but I'm paranoid that I don't have enough oxygen circulation in the cage. It is pretty much completely covered. I have also been misting every other day, which I am going to cut back on. I'm not sure the exact humidity but its much higher now. Will the high humidity mixed with low air circulation cause problems? I know about mold problems but I am using reptibark for substrate and I keep a close eye on all my wood hides.