We have been trough a tough time getting the site ready to install our pool. The area is a slope and its graded so the water coming down the hill will go around the pool, but the soil is clay and the flat pool base got soft when it rained. We had a contractor install a french drain to handle rain right around the pool, and put down a geotextile underlayment. Then then we put about 4 or 5 inches of 57 stone to raise the pool off the clay. At this point we let the contractor go and hired a new contractor to spread several inches of gravel dust on top of the packed gravel. He placed install patio blocks in the gravel dust for the uprights. This new contractor insisted that we would need a layer between the gravel and the gravel dust, or the rocks would come up, and he put a blue tarp!! on top of the gravel but under the gravel dust! His concern about the rocks is valid, but I am afraid the tarp will cause us more problems than it solved. I was thinking it would hold water and cause the pool to wash out from any little splash or small leak. We are so sorry we decided to install the pool! The summer is passing us by, and we want the pool up, but we also want it to stay up for years. Should we remove the tarp? Try to poke holes in it? Not worry about it? I was imagining that the gravel dust would form a packed layer but it is kind of soft and footprints sink in. I imagine it will filter down into the rock and rocks will come up without it. Any idea what to do at this point? Thanks.