February 18, 2025 3 min read
Above: A 2Hr A20 non-CO2 tank requires minimal maintenance and remains algae free. APT1 (lean water) + JAZZ enriched substrate (happy shade plants) and 20 PAR lighting.
We don't aim for an optimal R,G,B setting as research shows that plants utilize almost all of the visible light radiation from 400 to 700nm. However, we are precise in setting the light level - 50 PAR in this example.
We use PAR (Photosynthetically Active Radiation) because it measures what plants use. Unfortunately, neither watts (a measure of power consumption, not output) nor lumens (a measure of "brightness" as perceived by the human eye) nor lux (1 lumen per square meter) provide sufficient precision, especially when it comes to aquarium LEDs.
Proper PAR meters such as the ones from Apogee can be expensive, costing ~US$700. Inexpensive household Lux meters measure 'brightness' but unfortunately does not consistently match PAR, especially across LEDs / light sources.
PHOTONE APP?
A easy tool would certainly be helpful, so this well-reviewed app caught our attention. We compared the readings on a variety of phones (iPhone 11 to iPhone 15 and Android - Samsung, Google, Xiaomi) with the PAR meters we use: Apogee's MQ-500 and MQ-510. We used a 70gsm plain paper diffuser according to Photone's instructions.