leveling question

[asd161]

My wife and I removed and old pool and are in the process of setting up a new one. We were going to try to set up the new pool on the dirt base left from the old pool, but after pulling some stumps and weeds the base broke. I hear we are not supposed to build from bottom up, due to risk of sinking. We are thinking about using a tiller and a ground leveler. Has anyone tried this method before. Any other suggestions? Wish the pool was up now, but I want to do this right.