The ShowerPowerBooster SP1 is great for negative head situations, zero head situations, and situations where there is the minimum of positive head. There are plenty of simple ways of turning in on and off. The pumps take only 12 watts of power so the transformer will not overload a lighting circuit so wired into a lighting circuit it can operate whenever a light is switched on and off.
1.0 The simplest way to turn the transformer on and off at the plug socket.
2.0 The pumps take 12 watts each which is far less than a 100 watt light bulb so you can wire the transformer into the light switch or fan and it comes on and off with the lights or the fan.
3.0 An elegant solution is to buy a radio remote to switch the pumps on and off.
What Is Negative Head
Negative head is where the shower head or tap is above the water level in the cold water tank. Positive head is when the shower or tap is below the water level in the cold water tank. Zero head is when the shower head or tap is the same level as the level in the cold water tank. Should the water level fluctuate, (and it will if it is a cold water tank in a conventional home), the pump may transition from positive head to zero head, to negative head.