this is what i need to do for my big tank. It is pretty easy to make isnt it QUOTE]
yeah if your good with your hands, you'll need to have a box ful of wet sand to mold it in to the shapes you want, the best mixture for a reef tank is 1 part concrete(portland 1 or 2) and 5 parts crushed oyster shell, this mixture will make it so you can run water right through it and is ideal for benifical bacteria when mixing the oyster shell and concrete together use thick gloves and there is no exact amount of water to put in it it has to be between a cottage cheese and a slushy mixture to mold the best, wetter mix allows more capularies but is harder to mold, if you making arces or any rock that will support alot of weight use a mixture of 1 part concrete to 3 parts crushed oyster shell, let it dry for 24 hours till you you put it in FRESH WATER that is well aerated and circulating well when the ph 7.5-7.0 it should be able to go into saltwater but not with live animals watch the ph for several days in salt water that isn't moving or well aerated if it keeps a ph of 8.0-8.4 you should be able to put in with living animals for increased coralline algae put plastic sawdust or plastic scraps on the cement mixture while its still wet before you mold it in the sand.