Yes, there are additional tests that should be conducted to confirm the quality of the material used in the tank. These tests may include a visual inspection of the material, a hardness test, a tensile strength test, a chemical analysis, and a corrosion test. Depending on the material, other tests such as a stress corrosion cracking test, a permeability test, and a stress rupture test may also be conducted. It is important to ensure that the material is of the highest quality to ensure the safety and longevity of the tank.