HCA: Hermit Crab Association

I've been wanting to purchase some hamster sprays for my hermit crab tank. I wanted to know if these ones are safe or not. The types of sprays are: Wheat,Flax,Rice,White Sorghum and Red Sorghum.

I've been having constant problems with too high humidity. I have a 40 gallon tank, my water pools aren't too big, I have put in dried moss and dried wood. I have a digital heat and humidity guage so I believe it is accurate. My substrate is 5:1 ratio of playsand and eco earth and it's dry. The glas...