Just to clarify, a part is just a means of measurement. it can be a pound, cup, quart, whatever you have available. When I did my rocks, I used an old tupperware container. I think it was a quart size, but not sure. I would take 3 level containers of the Oyster shells ( local feed store had this for chickens ), 1 container of Portland cement, and 1 container of water. I used an old cat litter tray (completely cleaned out) to mix the 'mud'. I would then, if needed, add a little crushed coral, maybe half the container, to adjust the mud for consistency (not to soupy or to chunky). I had a rubber maid container with play sand to act as a form. I would dig a hole and fill with the mud and make boulders, arches, and I even made a few caves. 1 shape I call the UFO due to it being saucer shaped with windows. it is on the left side and second layer up from the sand. After the sculpture had set up for about 2 days, I would dig it out, rinse most of the sand off, and put it in another container of fresh water to let the concrete cure (this is not the same as the cure or cycle for the tank). This would take about 4-5 weeks depending on the conditions and flushing. I would change the water every 3-4 days and start checking the ph level looking for it to drop after the 3rd week. when this was good, I set the rock aside waiting to get the system ready for the build. I did luck out and got 100 lbs of dried 'live' rock to put in the tank. The fun was setting it up for aquascaping. My tank is 3 feet tall so I had to work over the edge and off a ladder. So I first set it up on a work table outside and used plastic pins to hold the bigger pieces in place. If I do it again, I will let the kids have the fun in the mud...
