A water tower is supposed to help you convey water via gravity to different places regardless of their elevation/topography. This is done by pressurizing the water through elevation.
In order to do this, the whole process has to be economical.
This means that you need:
1 Ample storage for your needs,
2 Ample storage to mitigate supply during power outages,
3 Enough rest time for your pump in between pumping,
4 Stress free use of the stored water.
In view of the above, will 2,000Ltr suffice?
How did you arrive at that water demand?
What is your source of water? Underground? Roof catchment? Water runoff storage?
What about future water needs?