cocotek blocks are much different then coco fiber, may i ask what brand of coco fiber are you using? i would recommend a drip/top feed setup on a timer, coco fiber has a tendency to become oversaturated and hold water for a long period of time, you wanna keep a close eye to how much water your girls are drinking, and how moist the soild stays, your plants will let you know if there thirsty or not, you really wanna watch overwatering in cocofiber cause you can run into root rot very easily, good luck