i have read about 50/50 coco hydroton mixes, I personally would rather work with one medium and not mix them except if the coco happens to be very fine grade and not airy enough. I am currently in the process of trying coco and 3 types of hydroton side by side. it is my first such trial but if i wanted to bet on it, i would bet in favor of hydoton all in, but i'll have to wait and see.