How should I plumb my tank?
Flexible connections should be used between the tank fitting and the pump to allow for expansion and contraction of the tank as it is filled and as liquid is withdrawn. A good quality flexible hose is best. We also recommend proper support under heavy valves and fittings that may be attached to the tank fitting. Please refer to the warning labels on our tanks for details. These plumbing recommendations will also extend the life of the tank by reducing stress on the tank.
Source: FAQs - Peabody