I use Reptichip, just tried five blocks of Prococo, it's exactly the same as Reptichip. I think it's the same as Exo Terra Coco husk only cheaper. The ten pound blocks of Reptichip and Prococo expand like you wouldn't believe. Just three expanded blocks will fill a 55 gallon drum! For prep I just submerge the entire block for 25 seconds on each side, drain for a few seconds and put it in a big plastic tote and it falls apart. I don't use any other chemicals whatsoever. It's fairly expensive but lasts a really long time, two months between substrate changes.