I want to find this leak before I add 7-800# of salt. Have air pressure tested all underground lines and they are ok. Cannot find a tear in the liner it was replaced 2 years ago. My pool is IG vinyl lined 20x40. When PB did liner he put a set of plastic molded steps in the shallow end. They were bolted to the aluminum walls and about two tons of concrete poured around the bracing. His son sealed the edges of the "clamping" strip that goes over the vinyl with a cheap kitchen and bath caulk. I am a builder by trade and complained to him at the time because I though a better quality caulk should have been used, mainly because submerged in water forever. He said don't worry about it. So yesterday he said that there is no way that the stairs are leaking that wouldn't happen for 10-15 years. He also said a 500 gallon a day leak would be a very small slit in the vinyl approx. 3/4 inch long. Does this sound right? Would that $40.00 a bottle Fix a leak the PB wants to sell me be worthwhile. Thank you in advance for any suggestions.