How do you level the ground for a rectangular pool?

Use sand , You need to have the ground opprox flat or level, and clear of all grass and weeds then spread 3 to 4 inches of sand . On a 16 foot pool use a 8 foot 2 x4 and a 4 foot level. Put a stake in the middle lay the 2x4x8 down with 1 end against stake then put level on 2x4x8, work the 2x4 around keeping one end against stake and the level on level. P.S. make sure 2x4x8 is straight. Fill in all low spots and spread the high spots. This is not easy to do,it will take 2 or 3 people. You should pack the sand. I had a Intek pool and used this process 3 years later the pool got a hole in it but the sand is still there. Go to the local rental shop and get a sod cutter. Learn how they work, youll be amazed what they do in a short amount of time for your DIY AG pool project, forget the Bob Cat unless your an expert real fact. Ryan makes the premium unit, rents for a small cost, and plentiful, they also work great for lots of other at home projects. good swimming getapool.com