I use one of those 15 gallon plastic tubs to re-hydrate a block of coco coir. It will take one 5 gallon bucket of tap water, and three tablespoons of epsom salt. It needs to be tap water for the mineral content. This and the epsom salt will let the coco precharge before adding nutrients. PH adjust to a 5.5 or so. Mix the epsom salt into the 5 gallons and pour about one gallon over the top of the block quickly. It will take about 15min for the coco to suck it up. Reach below the coco block and flip the entire thing after it has absorbed that first gallon. Then you will pour about one gallon slowly onto the center of the block every 15 minutes. After this is done let it sit over night or all day. You now have a full block ready to be hand fluffed and used.