Thanks again.
I know nothing of hydroponics, but I worked for a year in a lab developing a LIMS that extracted mass spectrometer data from plant, soil and water samples for determining optimum custom-made fertilizer (chelates?) for farmers and the like.
I was wondering if you could (or would) measure discrete elements - the lab worked on 3 macro (N,P,K) and 14 micro, from memory, including things like copper and cobalt, etc. It was fascinating. N,P,K ratios were critical, but the micro elements could have a major impact on yield and plant health as well. And each crop type was different.
When I looked at sensors for those sorts of things, you are right, they were off the scale in terms of costs vs what a hobbyist would spend on a discrete component. Crazy.
I had to google EC value - but of course that makes sense. Electrolytes. Nice.
Thanks for the hydrobuddy link too - that's great.
I have no garden here, nice sunny back yard but the garden space is full of bark and succulents, in a rental, so when I saw your project I immediately thought - hey, fresh veges!! I will be looking at this more closely in the coming weeks.