Pool bottom - sand/foam/pond liner

[marakech]

I know sand vs foam has been discussed many times on here, and I believe I've read most of those posts. I'm installing an 18X33 NBS in a space where I used to have same size with butresses. Last time I used sand and geotextile, footprints etc were quite prominent by times.

I had been thinking XPS foam + something like gorilla pad (always open to suggestions for the cheapest acceptable foam) and I've happened to run across lines used for ponds and I'm curious if anyone has investigated using something like that vs gorilla/rhino pads. If I understand correctly:
- Gorilla Pads and the like are 1/8"
- Foam seems like you'd want at least 1"?
- the better pond liners seem to be "45mm epdm". Never having seen or used this stuff, it seems like it would be ~ 1 3/4" rubberized material that's strong enough to be a liner for a fish pond and last 20+ years

So very roughly gorilla pad + 1" foam for an 18X33 would maybe run something like $750. Seems like I could get a similar amount of the EPDM for the same price and was just curious of there's anyone on here familiar with the material and know of any obvious reasons that I'm missing that make this an obvious silly idea?

 

[marakech]

I think I answered my own question as I realized that mils does not equal mm in the liner world - now it makes sense that it doesn't really seem to have been discussed previously :- )

 

[isee]

I bought a dozen of these for my 12x24 then put extra wide Gorilla tape on the seems and it has been great.

https://www.tractorsupply.com/tsc/product/4-ft-x-6-ft-x-3-4-in-thick-rubber-stall-mat

 

[marakech]

cool product, thanks!