Yes sir. Just 4:1 Salt to Cement. I have made about 60lbs of rock in all out of the three batches, and I still have a good 30-40lbs of cement left. Plus with a ratio of 4:1, one bag of cement will make ~90lbs+ of rock. But you would need 320lbs of Rock Salt
If you think about it, you can imagine how light this stuff is by basically thinking how big a mound of rocks the size of a mound of 320lbs of rock salt would be. That's pretty big! Now, it's only going to weight no less than 90lbs! Maybe about 100-120lbs because of residual salt. But you can fix that by just leaving it to cure a few more weeks after it is done with it's pH.