How to level the ground because my inflated pool dips on the lower ground... without adding sand?
Answers:
You want it level, you're moving material. Better to add sand if it's not too far out, than to dig down the whole thing.
To get it level, you can rent a laser transit at any rental shop. It's a one person rig and when set up, will let you know how high or how low you are from your reference point. If you had used one in initially preparing the bottom, this wouldn't have happened.
I don't reccomend putting anything other than sand and a tarp under the pool. Someone posted that concrete slabs would be ok, they'll shift and poke a hole through the bootm, as will skids.
Other answers:
Grab a shovel and start digging
Grab a shovel and start digging
There are several different methods that might work. First and foremost is perhaps trying a different area that might be a bit more level. If none is available, and you don't want to add sand or fill dirt, you most likely want a temporary solution.
You might want to try getting some small flat pieces of concrete (They usually are sold at most big hardware stores such as West Lake, Home Depot, etc) They are not that big, and used mostly for landscaping. You need to get the flat ones, not the ones that are curved. After you get them, pile them at the corner that is too low, and it'll raise it up. For further stability, and for the comfort of those in the pool, you may get a large couple of wooden palettes to put under the pool.