OTish... Automated water pump system

["howardsixtynine" <howardsixtynine@xxxxxxxxxxx>]

My Dad has asked me to automate his water supply system and I wonder
if you lot could recommend a source of the hardware for it.
There is a water tower at the top of the property, a reservoir
halfway down and a borehole pump at the bottom. I need to monitor the
level in the tank, and when it drops to 50% switch on the pump. When
it reaches 90% I open a valve at the reservoir that diverts the water
into the reservoir. The reservoir needs a sensor so that when it's
full it closes the valve and the water tower starts to fill again.
When the water tower reaches 100% I switch off the pump.
It needs to be wireless, the pump is 600m away - line of site with a
few trees in the way. The sensor and transmitter in the water tower
need to be solar powered with battery backup as there is no power
anywhere near it. I was thinking of a conductive sensor so that they
can just drop wires into the tank to set the levels.
The receivers and valve both have mains nearby.
I can build all the wireless control stuff from modules, but I wonder
if there's any ready made kit that might be suitable? And if not, can
anyone recommend a suitable transmitter and receiver kit?
Also, any idea where I'd get a motorised valve to fit a 90mm OD pipe,
on a very low budget? Secondhand and leaky wouldn't be a problem, but
it needs to be reliable.
Any suggestions much appreciated
H


------------------------------------