The Quad-Lock shell for both spa pool and balance tank is nearly complete. A twin wall of insulation provides a substantial reduction in heat loss. The balance tank and spa shell are a homogenous structure, the union of the two elements adds rigidity and strength to both. The end result is less stress placed on each wall, ensuring a long service life. In addition to this, the Quad-Lock panels act as shuttering, so there are savings on construction materials. To read more about the benefits of insulation click here.