Connect 50KL and shed tank for additional storage.

25 hose clamps per section (need atleast 40 more)
Another 3 25mm taps and 4 check valves.
Another couple 25mm Ts

A) Export branch (Tank → Backbone)

Ball valve (EXPORT enable)

Check valve pointing away from the tank (lets water leave tank, blocks water entering tank via this branch)

B) Import branch (Backbone → Tank)

Ball valve (IMPORT enable)

Check valve pointing toward the tank (lets water enter tank, blocks water leaving tank via this branch)