I know this is a cypress mulch topic,but the diff between the two is what helps keep humidity....so I'll make my basic comparison between coco husk and aspen...
Sho, I haven't had any issues with dust with aspen at all. I am using coco husk in one tank and aspen in the other....aspen doesn't hold humidity the dampness that the coco husk does. Still with having tanks ,I find myself still basically having to do the same things to both to maintain humidity. It's like if you wanna maintain a steady humidity,rack systems are the best bet..although to wett aspen will mold,had that happen once. I freaked out. But it was really my mistake,I had ran out of coco husk and added aspen by it's self to the cool side to fill in rest of tank,bad idea,no I didn't mix the two,left it separate,apparently didn't matter. My one tank that has aspen,never had I happen.
next weekend I'm Cleaning my tanks fully and will be using Eco earth in both..see how that goes.
i like aspen and have no problems at all..but for holding humidity better than you should go with coco husk,cypress mulch and Eco earth.
My eco earth bag came in the mail and it was damp when I got it,could seethe water inside bag