The unit currently reads

pH
relative O2
Ammonia
temp
Lux
PAR
PUR
Water level

There are no plans that I know of to add more readings

Relative O2? I did not know about that one


Sent from my iPhone using Tapatalk

The output for O2 refers to dissolved oxygen potential. This not directly measured, but is calculated, using an industry standard formula, from the other parameters that are directly taken. For this reason it only shows the maximum potential, not a true value in your pond or aquarium. The output is shown in PPM.

The graph is included as a guide so that your can see how the other parameters affect the potential of dissolved oxygen in the water. The biggest factor to the level is temperature and if the aquarium or pond get very warm in the summer, extra airation may need to be concidered.

There are some factors, such as atmospheric pressure, that are 'assumed' and not taken into account in the calculation. However, these do not have a very large influence on the output.