I have a very old pool that eventually needs some decking repair, but currently addressing issues as I can. Due to settling, I have cracks b/t the poured concrete coping and tile line all around the pool, but specifically looking for advice what to use to repair those cracks in the area of the attached spa. The water level is higher in the spa than the pool and when full is very close to these cracks. I've talked to a few companies for recommendations, and they all recommend a flexible silicone sealant vs grout or epoxy since those will crack. Any recommendation as to which product I could use? I need something that can be in contact with water (esp. hot water) and resist chemicals. I've found several potential options but looking for an economical option. Can I use the Boss 801 or 802 products?