This blog will likely change your mind about using Happy Bottom Pool Pad under your pool liner. I’m sure some people will give me flack for this one, but people ask me about Happy Bottom, and I am going to tell those who are willing to listen. I will also give you info on what works best for under pool liners and why.
 If you searched Happy Bottom you are like most pool owners, willing to spend a little extra money to protect your investment and improve your swimming pool experience. I commend you for this as it is a worthy cause. But sadly this product is not the answer to your quest. In short, my opinion is that Happy Bottom Pool Pad does nothing to protect, prolong or improve your above ground swimming pool.
Please read along as I explain in detail what this product really is, and why you should not use it during your pool liner change or swimming pool installation. From our blog

Happy Bottom Pool Liners are a Bottoms Up for pool owners|We all look forward to the times we share with family and loved ones around the backyard pool, and the pool is often a centerpiece to the yard-scape, which is why it is important to maintain ones investment. Unfortunately, Happy Bottom Pool Pads cause more frowns for home owners than anything else. Homeowners complained that they experience problems with rust as well as a problem with mold. The most frequent complaint however was the esthetics. Pool owners cited that the seams made the bottom of the pool unappealing to look at visually and cause issues with coming loose, which caused multiple repairs throughout the year.