Coconut fiber. 98% hatch rate. Had one not hatch which had not absorbed his yolk. Egg was twice the size of its clutchmate then deflated. Still waiting on clutchmate.
I use vermeculite. This year I have had a 99% hatch rate. Event that 1% could of simply been eggs not meant to hatch. The only thing is that I use a suspended incubation method so the eggs do not touch the substrate. I dont know think I would jump to changing substrates in a hope for better hatch rates. It might be other factors. Thus I am assuming you are having poor hatch rates, therefore the change in substrate?
We use vermiculiate here. Tried hatchrite and wasn't having any luck. We ended up loosing 3 eggs that go around. Since switching to vermiculite, we didn't loose any. We also use Albey's method of mixing it with the water to make sure it's accurate. But I think at this point, I don't check the site anymore. LOL.