I had a rat under my hot tub! it drained out, i waited a month then I tore up my deck that was built around it and found the dead rat! I then cleaned everything up and refilled it hoping to see the leak! We did not see the leak, but saw the water running off the slab of concrete, so it must be leaking on the very bottom under the styrophoam. I have two different kinds of bottles of stop leak for hot tubs, very expensive stuff!!! Doe's it work? Or just throw in the towel? I can not get under there any further to fix anything! please HELP!!!