Not only are there things wrong in your schematic but it's inconsistent with your description .
For example, you have an ON/OFF switch just to switch the Led and the alarm? And a fuse that protects the led and the alarm in series?
I'd suggest you write down your layout:
- Identify the tanks (T1, T2)
- Identify the float switches (SW1, SW2, SW3)
- Pair up your tanks with your switches (T1, SW1, SW3), (T2, SW2)
Write down, in short paragraphs, your needs:
I.E. - SW3 will turn on the pump and so on..
Post it here, I'll draw you the appropriate diagram..