Hello I am new to this forum and am hoping for a little help. I have had an ongoing issue with my spa wall spillway. It is faced with a quartzite flagstone and has been recently repaired because the flagstone was being undermined by the water. When my pool contractor made the repair he set one of the stones a little low by mistake so it makes a low spot on the top of the spa wall. This makes for uneven flow of the water over the top. Because of this low spot, when the pump turns off, the water keeps trickling over until it reaches the level of the low spot...annoying. It took many calls and arguments with my pool contractor for him to finally make it out to fix the original problem, so I really don't feel like dealing with him any more.
I have already taken out the stone that is low. My question is when the mason was repairing the spa wall he added something to the mortar mix. I am not sure if he added thinset to the mix or if he added thoroseal. I have both, but am curious if you guys have heard of this or if there is something else I can add to the mixture that would make it more water resistant.