Ok so the bad news I did have an underground suction leak, the good news it is fixed. The leak was the elbow coming out of the bottom of the skimmer. Thanks to a tip on here to use a ram bit we were able to drill the broken pvc out without having to replace the skimmer. To get to the leak we had to break out the concrete around the skimmer. Looking at the directions to install a new skimmer (we are keeping the old) it says skimmer must be surrounded by at least 4" of structural concrete in a monolithic pour using a cold joint. Can someone put this in terms I can understand? Also I would like to test it one more time before pouring the concrete - will refilling the pool put too much pressure on the skimmer if I haven't filled in the hole and poured the concrete? Thanks.