I have a noticeable hairline crack that spans approx. 3 ft on either side of the 'strainer/filter box' between the tile and pebble cote lining. I've had it assessed by 2 companies; a major leak one and a pool contractor. We lose almost 2" of water a week and live in So Cal with roughly 6 hrs of direct sun exposure daily. We had the pool recently drained to inspect the leak and it appeared that where the cracks are, that water was seeping down the pebble lining even though the pool had been emptied for at least 4 hours. They then dried after the sun was beating down on the area. The pool contractor advised that he would only be able to fully evaluate the situation after having pulled up the stone pavers that sit around the strainer/filter box. I don't doubt this but he also suggested that perhaps the best solution now is to just seal the cracks in hope that the leaking also stops. My fear is that if we do this then that may exacerbate an already existing structural issue by just applying a temporary fix. Would this be likely? Any other suggestions or should we have the pool contractor lift up the pavers for a full evaluation?
Also, when we purchased the house we were told that the previous owners did experience a leak in the pool pebble lining but it was not in the area where it was currently identified. We were advised in the sale that the leak was fixed. I don't know whether it's important but our pool only contains 1 return which is 2 ft under the strainer/filter box. There were 2 others but they were 'plugged up' by the previous owners. The pool contractor had never seen anything like this and assumed that there may have been copper piping where the returns were housed. Is having 1 return a bad thing? Our saline, solar heated pool has a hefty 2.5 horsepower pump and the force of the water is so strong that it's enough to transport you from in front of the return to mid way down our 22ft by 12 ft pool in a few seconds.
Any advice, help would be greatly appreciated.