concrete or dirt ?????

[griz07]

My perimeter for my 18ft AGP is spot on ready for the patio block and bottom rail BUT I noticed this evening after 4 inches of rain the past 2 days that 2 areas in the inner of the circle, roughly 2x2ft are holding a puddle, maybe a inch or so deep. Should I fill these with concrete or maybe dirt ? I will be using foam for the bottom and foam cove. Suggestions ????

 

[CJadamec]

I would use sand, which is what would normally fill in those gaps before people started using foam. You definitely wouldn't want to use concrete that would just make an awful mess.