Most importantly, light is used in photosynthesis, the process which produces food for all aquatic plants and most coral. It is therefore obvious that aquarists would want to measure light to ensure that plants and coral thrive.

Aquarists understand that care should be taken when choosing light systems, as the needs of different aquatic biotopes vary. It is equally important that organisms being purchased should be suitable for any existing biotope. To know if they are correctly matched and that lamps are performing correctly over time, the seneye device helps to look at light in two main ways: spectral distribution and intensity (quality and quantity).

Do I need a seneye, why not just use my eyes? The human eye is good at seeing colour and comparing colours when they are shown side by side. Subtle changes are difficult for us to see and interpretation will vary from person to person. The human eye sees certain colours more easily than others which can make it difficult to judge the intensity of lamps against each other when they have different colour (k) outputs. The human eye is very poor at judging light intensity as it is designed to work at very low and very high light levels without us knowing. The combination of these factors means an impartial device is needed.

The seneye device allows you to see light in many conventional ways as described in the following text; however, an important aspect of what it does is to also allow a controlled method of logging light over time. As discussed earlier light is food to plants and as such looking at how much is available as a one second snapshot every month doesn't give an accurate total picture. The quality, quantity and duration of phototropic periods are essential information when trying to establish growth rates, which is why the seneye logs it.

Even if you're not worried about growing plants or coral, many photochemical reactions occur in aquariums which cause parameters to shift. Lights often cause heat and as such can cause the temperature to rise, changing NH3 levels. Without logging light the real cause may be missed. Another example is that during a 24 hour period pH may change as a result of light levels causing photosynthesis which uses CO2 (carbon dioxide). This change to a higher pH will cause harmless ammonium (NH4) to be converted to toxic ammonia (NH3).

Understanding light is also important for being able to tell if you have too much light; a good example is to track light over time for understanding green water and algae growth. Often it's not the light provided by the aquarium that is exacerbating an algae problem, mounting the seneye in reverse looking out of the aquarium and logging for a day will often show that ambient or environmental light is reaching the aquarium in high levels.

We hope many thousands of aquarists will be using seneye devices to data log their light sources and this data can eventually form a very useful set of benchmarks to help others. Furthermore, all data is logged in its raw form from the device so if equations and calculations are improved over time (which we expected) all historical data logs can be recalculated. Data can also be interrogated in its raw form when we create new modules on the seneye.me website. It's going to get really exciting as modules are developed specific to aquarists' needs.


The existing seneye hardware platform already collects a lot more information than is used in the readings above. It is our intention to see if it's possible to develop modules for aquatic biotope based analysis such as PUR, PAbR and PArR readings that use the data collected from the existing seneye hardware.