How do I use a fogger for a red tailed boa in conjunction with a humidistat?

I am having problems keeping humidity over 30%. I have a long 29 Gallon tank, red tailed boa is 18 mos. I would like to automate humidity controls and have a zoo med hygrotherm ht-10 with a humidistat. I have tried the exo terra ultrasonic fogger in different configurations with very little luck. What sort of water part do I need to keep the snake safe with the ultrasonic fogger? Or would it be better to sell the fogger off and try another humidifier?