I don't replace the substrate with the moss. I use several softball size clumps of the moss. Just get it wet and wring it out like a sponge, leave it damp. you can place some in the snake's hides or out in the open in the corner. I usually put a clump under/above a heat source as this helps the water to evaporate thus raising the humidity. Keep in mind that this bunch of moss near the heat source will dry out quicker, at least mine do. You said you bought a temp gauge, what type is it?