I am in the middle of having a 16x32 inground pool installed and the pool floor was finished and liner layed in on Thursday and on Sunday while the water was filling up my daughter got in and was walking around the shallow end and several large indentations formed where she pushed off with her feet so I walked in and was able to push down and create indentations also...mostly along where the pool starts to slope into the deep end but also around the edges in the shallow I end. I have called our contractor who is to come back out today but wanted second opinions for when he gives me his cause for this and solution. I believe they did a poolkrete bottom. Thanks!