Is the weight of your pool water pulling down on the liner causing your above ground pool walls buckling some more?
Does the liner still appear to be centered with no wrinkles, or creases, and no additional lining anywhere? Then the issue could due to the weather becoming cooler.
The tension is most likely caused by a cold liner. So, stop filling and only resume during warmer days. You will find this to be greatly reduced on a warm day.
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Why is My Above Ground Pool Walls Buckling while Filling [AT THE TOP]? ANSWER HERE!
At times we think reaching over the wall and pushing it back out while continuing to fill the buckle will fix the issue but this is not always the case.
I recommend checking to see that the liner is not pinches and is smoothed out. Why? Because as the water fills the pool bottom, you may see some air trapped under it. That can work it’s way over time and can lead to a bit of additional tension to begin with.
A much better approach would be to fill it slowly. Something about a foot a time to let the liner settle well. For best results, fill it out on real sunny day (I mean really sunny). That will heat the liner some and make it a bit pliable.
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In many cases, no matter how much you smooth it out it is still going to need some time to settle a bit. I guess to make a short story long the buckling is pretty normal.
Let us know if our guide worked for you! Cheers!