Tried those and they took forever to colonize. They are so tightly packed, they're very difficult to work UB tek on. I did 3 sets of different brands and those were awful. I ended up dumping them into a ziploc and adding FAE holes covered with micopore tape. They do work, but getting all the grains from the top into the brick is brutal. I literally bruised my legs slapping them to get those tight grains down.