Underlayment questions for replacement pool

[Bigric]

We're replacing our well-worn 22' Coleman with a 24' this weekend and I'm selecting materials for underneath the liner (we did it straight on level dirt before). I'll be using extruded polysterene panels underneath and have a couple of questions:

• Can I use pea gravel to level underneath the foam panels? Or do I need to use packed earth?
• Will 1/2" panels suffice, or do I need to go 3/4"?

Thanks in advance!

 

[duraleigh]

Pea gravel is the best. Normally won't wash out and compacts very easily

 

[duraleigh]

You could also use a coarser graded rock, if you can find it