I don't know how people here feel about eco earth, but I love it; it is compressed coconut bark. And if you use a water spray bottle to mist the substrate as needed, that will give the tank the humidity you want. Just don't let the substrate get swampy as that could cause scale health problems. Damp is okay - especially if you have dry places for the snake to retreat.
And feel free to place a towel over a part of the tank. That also helps keep the temps and humidity up. Just ensure the tank gets good air circulation by removing the towel on a regular basis.![]()