The light graphs are broken since 3.0 due to significant changes in pwm profiles. 3.0 introduced a host of different pwm profiles that can be applied (including lunar, sine , random profiles...) and we didnt have enough time to implement those in the charts. 3.5 (will be released in couple of weeks) will have interval (auto), fixed and diurnal charts (its already in master, i just have to cut a release).
Currently the only i2c based ADC thats supported is the official ph driver (pico board from blueacro also utilizes an ADC based on i2c). If theres a common chip that you think will be useful for general audience, we are happy to add a driver for the same. Since 3.0 HAL inclusion, adding new driver is pretty straight forward (which is why we have now so many different types of drivers in reef-pi).
Thank you as always :D No problem for the lights graphs, It's not a problem :D
Regarding the ADC driver maybe the ADS1115 could be a nice IC, there's a tiny Adafruit board ready to use... It only has 4 channel but for most application they should be fine ;) It also works with I2C :)
Another, at least in my opinion, great possible add could be this module:
9.45US $ 30% di SCONTO|PZEM 004T Nuova Versione TTL Power Energy Watt Meter AC 220V 100A di Energia Elettrica Volt Amp PF Frequenza Kwh Voltmetro Per arduino CT|Contatori di energia| - AliExpress
Smarter Shopping, Better Living! Aliexpress.com
The only downside is that it works with serial communication, and a few mods are required to make it work with 3,3V.
Nothing so complicated, only a 1K resistor to solder between two points on the pcb..
P.S. if any of you is searching for an IC to extend the I2C lines, maybe to connect the control box to the PWM expander on the hood, the Texas Instruments P82B96 chip works very very good! I'm testing it with more than 10mt (32ft) of CAT5 cable without any problem!

