I took OCreef.com up on there offer for a great deal on the Seneye Aquarium Monitor and will be writing a review of it here. Seneye Reef monitors all of the following: (from the ocreef webpage) Temperature - constantly monitors water temperature, so you can get an alert if your heater breaks or your chiller fails. Free Ammonia - monitors the highly toxic free ammonia (NH3) at very low levels, so you can stop your fish from dying from Ammonia poisoning. pH - the Seneye monitors pH in your aquarium between 6.4 and 9. This range is ideal for most aquatic life and by focusing on this range increased accuracy has be achieved. Water Level - readings are only taken when the Seneye device is in water, no false readings. LUX - monitors ambient LUX and can be used to take direct LUX readings, understand how your light degrade over time. Kelvin - understand where on the kelvin range your lights are and how light can change over time. PAR - monitor the Photosynthetically Active Radiation (PAR), understand if you have the correct quantity and quality of light for your corals or plants.