I did not invent this, it is from someone called monstermitch who wrote it. But I do use the method and think it should be passed on fully as it was originally written. This is not my grow and I am not taking anyones credit. I am simply sharing education and passing it forward. I put this in someone elses thread for a visual but I thought why not give this great method its own thread so you can all see it and get out the knowledge more. I vary my set up a little from this I now put a little fish pump on top even if a very small one so I know it is getting fresh O2 when popping up shroomies. This is NOT needed but I do it to ease my mind and increase yields. I suggest the first time you dont vary at all just follow detail for detail and you will be rewarded. I use This Method for making monotubs now. I suggest you do the same if you can find the tubs. Supplies Needed: 35 gallon blue tub with locking lid from Sterilite . I've done much bigger and smaller. This is perfect for me. To fill this tub, you will need the following: 10 dry pounds of bulk substrate 6 quarts of colonized spawn Hole drill bit that is 2 inches in diameter. Piece of cheap plexi-glass that is 12x24 inches. fits so perfect. It is great. Roll of gorilla tape. Duct tape will loosen in a wet, humid environment; gorilla tape will not. Bag of poly-fil . Poly-fil is a non-organic material not habitable to contaminates. It provides excellent air exchange and filtration. I suggest not using tyvek or micropore tape. Neither is suited for this type of application. Piece of black 3mil plastic or a black trash bag, cut to ten inches longer and wider than the bottom of the tub. The corners can be cut as well to round them a touch. _______________________________________ The Procedure: Stand the tub upright and secure the lid into place. Mark a rectangle on the lid. Make it one inch less than the plexi-glass' dimensions all the way around. So your marking will be a 10x22 inch centered rectangle. Cut this rectangle out of the center of the lid. I use a propane torch and a hot knife to cut the plastic out along the marked line. The plexi-glass should sit on top of the cut-out opening and have an inch of plastic to support it all the way around. Remove the protective coating from the plexi-glass on both sides. Tape the plexi-glass to the top of the lid using your gorilla tape. You may tape the underside as well if you wish. Tape the plexi-glass well, having a two inch overhang of tape past the edge of the glass going outward. The inner edge of the tape may line up perfectly with the edge of the plastic under the plexi-glass. So the tape will cover one inch of glass and two inches of plastic all the way around. The finished product is sleek and effective. Set the new lid aside so you can make holes in the tub. Four holes in each of the two longer sides. Eight holes total in the tub. The bottom two sit where the bottom of the hole is 4.75 inches from the bottom of the tub. Each outer side of the holes are 5.5 inches from the outer side of the tub. The top holes are 6-8 inches directly above the bottom holes. Putting them each 5.5 inches in from the outer sides. Hole placement is critical to this working properly. The substrate has to come right up to the poly-fil so the carbon dioxide can expel properly from the casing/substrate surface through the bottom holes. The top holes will allow fresh, poly-fil filtered air to enter the tub and circulate. This circulation and expulsion is what the mushrooms need to survive. Drill out the holes with your hole saw bit and clean up the mess. Drill one hole at a time and do it patiently as to not crack anything. Wipe out the tub now with vinegar. White distilled. Now wipe it out with isopropyl rubbing alcohol. Rub down the inside of the lid too. Get all of the plastic shavings cleaned up well. Place the lid on the tub. Stuff the holes with poly-fil. You want it roundish on the inside, not all crazy, the outside can be crazy. To achieve this you put the poly-fil in from the outside --> in. Remove the lid, mist some isopropyl into the tub, and place the black plastic in the bottom. Tape it a bit to hold it up on the edges. Place the lid back on and spray oust all around the tub, and you are ready to go. Once full with bulk substrate/spawn, leave the tub closed to colonize. Elevate the tub on milk crates or on a shelf. Most contaminates are within the bottom foot of the air, so keep your tub up above that at all times. Cover the top glass with a towel or whatever to block the light. Peek through the glass and condensation once every few days to check for cobweb or any other contams. Once fully colonized, you may case if you wish, or leave it be to flush. If you case, let it colonize again for a few days before exposing to light. Keep a fan oscillating in the room the tub sits in, leave it on low and don't point it directly at the tub. Keep the room temperature around 74-77 degrees, even when the tub is just colonizing. Never open the tub to mist or whatever, leave it alone.