Exact same problem re: absorption happens with coco fiber, both short fiber and long fiber types.
There are tons of supplier out there, from exotics, to greenhouses, example http://www.greners.com/i/growing-media/coco-based/cocogro-coir-fiber-5-kg-bale.html
IDK either, Poec54 and a few others use just top soil. I wonder if they encounter that?
Only if kept too humid without enough ventilation imo.
Same here. Works perfectly.
Virtually all soils will mold.... if they are organic. Only organic soils will mold because they have something for the fungus to break down. Inorganic soils (made of minerals instead of compostable matter) will not mold and is a prefferable substrate over organic matter. Try a good loamy clay/ sand mix and you will find better results and better behavior from your earth dwelling species.
That is basically what I stated that most all substrates will mold without proper ventilation. The problem arrises with mold for one of two reasons or a combination of the two. #1 lack of ventilation and #2 keeping the substrate too moist. Many new keepers need to keep in mind that wet substrate does not equal humidity but that is for a different thread. I personally have no issues with mold, simply stating that most of the more popular substrates have a higher potential of molding compared to coco fiber which is more acidic which helps it resist mold a bit more. I use have used this product for close to ten years in moist lay boxes for a few species of geckos we breed as well as for our T's and have had great success with it. That being said, most all of the substrates discussed when put in the correct setup will work very well.
I keep my roaches and some of my Ts on Scott's topsoil. Haven't had any gnats yet, but I do get fruit flies in the roach bin from time to time.