This oxygenator works by charging the battery when the sun is shining & then using the stored energy when you need it. It has two modes: Daytime Operation Comes on in the daytime. Best for ponds with no oxygenating plants. Night-time Operation Comes on at night. Best for ponds with lots of oxygenating plants 3m of cable from the solar panel to the pump. 2 air stones with 2m long tubes.