Tell us more about your setup. Temps, humidity, everything.

I keep around 80-95% humidity. I use plain perlite as my substrate with great success. I like it better than hatch-rite or perlite/vermiculite mixtures.

I keep my temps at ~74 degrees. Room temp, no heat or cooling.

All I do is use perlite, soak it in water, squeeze out as much water as I can, and place it in a tupperware. I cover the tupperware with its top. Bam, egg container. It really is that simple. Perlite is great because the bottom layer can be pretty wet to provide humidity and the top layer can be a bit drier to keep the eggs from direct water contact. No precise mixing required at all.

I had a few clutches go sour early this year, and I blame it on fluctuating room temperatures during summer. No A/C causes problems with that. I just had my last clutch of the season hatch out on x-mas day.