I'm testing the water before i add to plants, and then i test the run-off. after i have tested the run-off i then test the soil pH also. I maybe a little ocd but i figure its better to be ocd than not at all. I am open to other things as well. for example, what is the best result of lighting....is it better to have 24/7 or 18/6. Is the 24/7 too much stress for the plants or should it be ok with that for the veg state?