Introducing the Milwaukee Luxmeter. To encourage photosynthesis, you need to provide a certain amount of light. This portable light meter will give you the measurements you need quickly.
This lightweight, ergonomic light meter is fitted with a waterproof sensor and a large LCD screen. You'll be able to read data to within + or - 6%. An automatic shut-off after 10 minutes protects your device in case you forget.
Operates on one 9V alkaline battery (not supplied)