This is a great idea. PAR data, to be useful has to include the light manufacturer and model number, preferably, the bulbs data - manufacturer, color temp., age, etc., and the distance of the light from the sensor when the data was obtained. Plus, we need to be alert enough to know that measuring light in a clump of plants doesn't tell you a whole lot, except that some plant will grow in that light intensity. We also need to know if there was a glass top on the tank and, if so, how clean it was. Ideally we would need PAR numbers for at least 2 distances from the light to the sensor.
For plant related data, we would want the PAR at the top of the plant, at the bottom, and maybe at the distance where the leaves are no longer growing well. Characterizing how well a plant is doing with that light will be difficult.