Hi you have a choices in regard controls for a two pump system
1. You can buy two controls one for each pump
or
2. you can buy a dual controller
http://www.gardinerpolesystems.co.uk/acatalog/Digital-Liquid-Logic-trade--Pump-Flow-Controller-LIQUIDLOGIC_DUAL.htmlThe dual controller takes a single 12V power source and will operate two pumps independently of each other. you calibrate each pump separately. The unit has separate DE detection for each pump plus the usual volt meter and PS detection.
As for fitting with the dual you have six connections two to the battery the two leads each out to the pumps. If you have some basic electrical knowledge fitting yourself is no problem. With a self install it is worth remembering that
1. Ensure correct polarity is observed when connecting to the battery
2. Fit the fuse in line on the Red cable between the battery and controller
http://www.thehub360.com/correct-fuse-use.html3. Ensure the cables are as short as possible to avoid volt drop.
The Dual controller is rated to 15 amps as it has two pumps drawing current across it.
It is also available form other stockists.