So one could work for a few of themThese things read almost instantly. I keep them in a jug of water and after I mix toss them into the jug of nutes and bam < 5 seconds I'm feeding or adjusting. Much better than my pen. Plus my pen is hard to mount on the top of container. This just toss them in and don't care if the whole thing sinks. Head is kind of mounted to the shelves and the sensors are 6' or so.
Interesting