What should the onboard booster tank be at least to operate the siphon/strainer effectively?

To operate the siphon/strainer effectively, the onboard booster tank should be at least half full. This level ensures sufficient water volume and maintains the necessary pressure for the siphon to work correctly. When the tank is sufficiently filled, it helps to prevent the pump from drawing in air, which can cause cavitation or pump failure. A half-full tank provides enough head pressure to create the desired suction needed for efficient water flow through the strainer.

While completely full or three-quarters full may provide enough water, these levels are not necessarily required for effective operation, making half full the most efficient and practical choice. Having at least one-quarter full could risk inadequate water supply, which may impede performance given the demands during firefighting operations. Thus, maintaining the tank at least half full is essential for reliable siphon and strainer function.