Its simple
Hatchrite is a reptile product that costs more than vermiculite which is a garden product.
Ive always just used vermiculite. Its cheaper and I rarely have humidity issues.
I am currently using hatchrite, but I am also an avid user of perlite which is basically the same thing. I have never had a problem with mold, and rarely ever loose an egg except for infertile ones. I actually use a hovabotor which I filled the bottom around the water channels with perlite which you can purchase from home depot or lowes. I wet the perlite in the bottom weekly and keep a constant humidity level of 90%.