"liner" under the pool


In The Industry
Jul 31, 2019
I have been using sand under my UG pool Intex/summer waves for several years. last year I up sized to a 18' round. I felt like it was hard to get the liner smooth over the sand. Is and what ground liner could I use for a smoother bottom and added protection.

My pool sprung a leak this season and washed away a "hole" under the liner which looks like caused a larger "tear" in the liner. I lost water below the skimmer and burnt out the pump before we noticed the problem. ( we where running the pump 24/7 trying to clear up the water....any how

What ground liner would be good?


LifeTime Supporter
Aug 14, 2013
south east Arizona
Welcome to THE place for good, sound pool advice! Lots of people put foam board or those "puzzle piece" interlocking floor mat pads under their pools. Do a little search, there are any number of posts about the topic.

And for clearing your pool, do read the pool school articles, think about getting a good test kit and learn to have the cleanest, safest, (and easiest!) sparkling pool water without extraneous and overpriced miracle junk dumped into your pool sold to you by pool stores.
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Gold Supporter
LifeTime Supporter
Jul 16, 2010
Portland, Oregon
We didn't do sand this time, but did do two tarps over the sifted (for rocks) dirt that had been meticulously leveled.

When you fill, get in and start spreading out the bottom of the liner as soon as you can. If you get even 1" of water, it's nearly impossible to get wrinkles out. Get on your hands and knees and push any wrinkles from the center towards the edges.

Foam boards are popular as well, as noted above. Permanent (or semi) ABGs always have a foam board pad underneath. I've never found need to go that far with my Intex types though. YMMV.

Consider your dead pump a good omen... those things aren't very good. Invest in a 14" or 16" 2600gph (or better) sand filter and pump combo for next year. You won't regret it. Check for sales over the winter. I saw a 3000gph combo for $189 on Amazon less than a week ago.

Flex seal tape may work with your liner tear to patch it. Just make sure to patch from the inside, and make sure the patch is much larger than your tear. Inches larger... Might want to double up on the outside too.