GrowKave

You are asking the real questions. Testing your water accurately means having a consistent baseline and an accurate probe (strips are okay if you are not worried about pH seriously but this is really only okay for soil IMO). If you list all micro and macro nutrients for cannabis and then check absorption ranges for them by pH, there are windows in the pH spectrum that are good for cannabis and others that restrict whole nutrients. pH can ruin everything for the plant, even if all the needed ingredients are sitting right there. As is pointed out below, pH and salts also play a huge role in osmotic pressure and other mechanism for the plant. A good probe is around a hundred USD, that often includes multiple buffered control solutions for recalibrating the pen and a spare probe sensor (as they do not last forever). They can last for a long time. I have a cheapo one that I have to rebuild and calibrate often. A good in-line sensor is about the same, just need more pieces to bring it to the cloud or automate it. Amazon has some pH/EC 24/7 uptime Bluetooth connected probe with a control panel for under a hundred, the same from any scientific supply store is a few hundred. Here we get to a somewhat fun point in botany. No, there is not currently a tool out there which you click a button and it says 'beep beep your medium/solution is missing nutrient X'. Monitoring pH and EC ensure that things are available to the plant. At the end of the day, micro deficiencies are rather rare and macro deficiencies are easily discerned. You would do the investigation of which nutrient is the problem by means of a observing your plant, and applying a dichotomous key, such as that from KiS Organics. We could make such a tool but then you'd need correctly labeled data because it would also rely on visual observation and deductive reasoning coded based on the key mentioned above (so imagine how unlikely that is when you can take the top 100 growers on GD and give them a picture and you'll get a wide range of thoughts). Training data really is the issue here. It can be a little weird that things are so dynamic in botany/biology. Cannabis pollen always got me. The range of sizes for cannabis pollen and the wildly varyign moisture rate makes the pollen either tiny or gigantic (relative to other species' pollen) and either floats for miles or for centimeters. Let me give you a thought expoeriment, without destroyign the sample how would you discern a given spore as cannabis pollen?