I just got 40 year old indoor pool drained out as I am helping with a remodel project. The pool has recently had issues with fluctuation in water level. Some days the level will drop a full couple of inches, and other days it will keep a consistent water level. There is nothing leaking pump/plumbing wise and I can not seem to find where this large water loss is going? My thought at this point is it has to be cracking in the pool concrete foundation, as the pool was bonded at some spots years back. I have bought a pool bond kit from http://www.emecole.com/pages/foundat...pair-kits.html to try and reseal cracks? Has anyone used this product? Secondly there is like a check/spring valve at the main drain on the pool that still has water coming up through it after draining the pool shown in the picture. What is this and should water be coming back up after draining? Pictures coming. Thanks for the help!