Swimming pool stairs manufactured prior to 1996 were meant to be supported by the by the ground underneath. Unfortunately, the ground settled over time, causing the stair treads to flex with the weight of bathers. The flexing causes cracks to form in the treads, and then water loss. We found epoxy is not the best material to use, because it seemed too hard, and over a short period of time, it broke away from the original step, and caused our second tread to break elsewhere, and the leak started again. We used a product from poolstepspecialists.com, who were very helpful, and for under $200,we were able re-support and fix our treads, and made the pool look great.