I am so happy to find this thread. I just had a pool built and my spa is integrated within my pool with tile no coping on top of spa. The spa water doesn't heat properly as the pool water is always overflowing into our spa. I would appreciate any advice how to have the pool company fix this issue. We don't have an overflow mechanism installed. I've been told that this is important so that the pool level doesn't go over the spa every time it rains or there is somebody swimming in the pool causing a disturbance in the water level. I don't believe we have a separate spa pump. The pool company is just proposing to raise the spa wall an inch which is currently just below the middle of the tile line. While i agree the wall of the spa needs to be raised it doesn't seem to be the only thing needed to solve the issue. I would greatly appreciate some advice so we can solve this issue and start enjoying the pool and spa.