Infinity Spa
This is the term used when a spa spills into an adjacent swimming pool and the water is filtered as one body of water.
This is a mini infinity edge spa. The benefits of this system is the spa water can be cycled through the main body of water in the pool to keep it fresh.
So if you have a pool spa combination on the same filtration system you can heat both bodies of water at the same time to a temperature of say 30° then swap to the spa only and increase the temperature to 38°-40°