[Stephen burton]

How easy is it to install a flow controller and what would I need to do it

[Ian Sheppard]

The majority of controllers available on the market have four cables. Usually red and Black to the battery, Brown and Blue to the pump.
These are Direct current devices so it is important to make sure the polarity is correct when connecting to the battery
Red is to the positive terminal
Black to the negative terminal

You should also fit a fuse between the battery and controller on the red cable to protect the controller against current surges. With most controllers you should not fit greater than a 10 amp fuse unless the manufacturer advises a different reating.
Ensuring good connections and as short a run of cable as possible will also reduce volt drop. 
https://www.linkedin.com/pulse/volt-drop-its-effects-wfp-system-ian-sheppard?trk=mp-author-card

There are a number of controllers in the market and most will come with a user guide.

another article that may help is https://www.linkedin.com/pulse/cable-electrical-system-maintenance-ian-sheppard?trk=mp-author-card

[Tom White]

Here's one for under £15.00.  My original one has been going for over a year now with ZERO problems.

http://www.cleanitup.co.uk/smf/index.php?topic=192847.20