The flush tank should have a capacity that is at least 10 per cent of the capacity of the main tank.

It is ideal if the flush tank has its own fill hose from the fresh-water source to reduce the chance of contamination, along with a ‘one-way’ or ‘check’ valve in the suction line so mixed product cannot move from the main spray tank into the flush tank. 

Flush tanks are very important for being able to easily flush the pump, spray components and nozzles in the field, especially if the main spray tank has not been completely emptied.