If they are on the ground you don't need to strap them down. The water will hold them down nicely.

Normally, when you lay something on the grass for the summer, you expect it to get really disgusting underneath--the grass dies and there are worms and grubs under there. But with a solar panel on the ground this will not happen.

The grass will die, but it will be baked. It won't be soggy and full of bugs, but will be dry and hot. When you roll up the panels it won't be disgusting.

But there's another interesting twist to panels on the ground. They will transfer a portion of their heat to the earth, heat that you would think is lost. But it's not! That heat will pour back into the panel after the sun has passed and, for a couple of hours, will CONTINUE to add heat to your pool.

Remember: As long as the water from the panels is warmer than the pool, even by 1 degree, it's still working.