i used peralite this year for two of my eggs. theyre not looking too hot. it was a test, and i feel its failing. the eggs are still healthy, but ive noticed mold growing on them recently. last time i use it. ive never tried hatchrite, and ill give it a shot if you have such a high hatch rate, ive always used vermiculite with no deaths except mess ups on my part, too higgh of temp, too much flux etc.