I just put up a 12x24x52 above ground pool. We filled it over night. This morning it looks good everywhere but one end. On the 12 foot wall it has a low place just in the middle. So it's bowing just in the middle. Can we Jack that one leg up and put a cap block under it. Thank you for the advice.
I'm sure the textbook answer is to lower the water and realign/level that one post or section. 
But if you look around here long enough on the forum, maybe enter some keywords in the search window (top right), you'll see previous posts where some owners had some good success manipulating one spot/leg long enough to boost it up a bit. I'm sure it can be done, but your safety would be #1. Be careful!