Third party Operating System are also available.
PID control coefficients adjustment should by performed empirically, using the specific equipment and with full load. The idea of the adjustment is to find coefficients that don't lead to 'under-guiding' (corrections are too slow) or 'over-guiding' (sinusoidal oscillations with increasing amplitude).
It is recommended to choose the range of values from 10 to slightly more than the recommended value during the selection of the proportional coefficient (see 'Info' block) and move through this region with the step of 10, looking attentively, how the result of the guiding will change.
The selection of the integral coefficient is recommended to perform, if there is constant impact in one direction. This coefficient will allow for the faster correction of the impact, because it takes into account the previous guiding history.
The differential coefficient, as has been said above, is disabled at the moment.
Do you have any photos of the Raspberry Pi all wired up with the plants in view? Also, can you describe how you got the system working? Maybe provide some steps for someone else to set up something similar.
You could find some photos, screen captures and the setup information by downloading the "AiGO user manual" that is located at my last post within this thread.